16 files changed, 236 insertions, 110 deletions
diff --git a/docs/installation/alpine_linux_en.md b/docs/installation/alpine_linux_en.md
index a5683f18c..c37ff0c63 100644
--- a/docs/installation/alpine_linux_en.md
+++ b/docs/installation/alpine_linux_en.md
@@ -1,25 +1,14 @@
 # Installing on Alpine Linux
+
+{! backend/installation/otp_vs_from_source_source.include !}
+
 ## Installation
 
 This guide is a step-by-step installation guide for Alpine Linux. The instructions were verified against Alpine v3.10 standard image. You might miss additional dependencies if you use `netboot` instead.
 
 It assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.linode.com/docs/tools-reference/custom-kernels-distros/install-alpine-linux-on-your-linode/#configuration). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su -l <username> -s $SHELL -c 'command'` instead.
 
-### Required packages
-
-* `postgresql`
-* `elixir`
-* `erlang`
-* `erlang-parsetools`
-* `erlang-xmerl`
-* `git`
-* Development Tools
-* `cmake`
-
-#### Optional packages used in this guide
-
-* `nginx` (preferred, example configs for other reverse proxies can be found in the repo)
-* `certbot` (or any other ACME client for Let’s Encrypt certificates)
+{! backend/installation/generic_dependencies.include !}
 
 ### Prepare the system
 
@@ -29,7 +18,6 @@ It assumes that you have administrative rights, either as root or a user with [s
 awk 'NR==2' /etc/apk/repositories | sed 's/main/community/' | tee -a /etc/apk/repositories
 ```
 
-
 * Then update the system, if not already done:
 
 ```shell
@@ -40,7 +28,7 @@ sudo apk upgrade
 * Install some tools, which are needed later:
 
 ```shell
-sudo apk add git build-base cmake
+sudo apk add git build-base cmake file-dev
 ```
 
 ### Install Elixir and Erlang
@@ -56,6 +44,7 @@ sudo apk add erlang erlang-runtime-tools erlang-xmerl elixir
 ```shell
 sudo apk add erlang-eldap
 ```
+
 ### Install PostgreSQL
 
 * Install Postgresql server:
@@ -76,6 +65,12 @@ sudo /etc/init.d/postgresql start
 sudo rc-update add postgresql
 ```
 
+### Install media / graphics packages (optional, see [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md))
+
+```shell
+sudo apk add ffmpeg imagemagick exiftool
+```
+
 ### Install PleromaBE
 
 * Add a new system user for the Pleroma service:
@@ -107,7 +102,7 @@ cd /opt/pleroma
 sudo -Hu pleroma mix deps.get
 ```
 
-* Generate the configuration: `sudo -Hu pleroma mix pleroma.instance gen`
+* Generate the configuration: `sudo -Hu pleroma MIX_ENV=prod mix pleroma.instance gen`
   * Answer with `yes` if it asks you to install `rebar3`.
   * This may take some time, because parts of pleroma get compiled first.
   * After that it will ask you a few questions about your instance and generates a configuration file in `config/generated_config.exs`.
@@ -115,7 +110,7 @@ sudo -Hu pleroma mix deps.get
 * Check the configuration and if all looks right, rename it, so Pleroma will load it (`prod.secret.exs` for productive instance, `dev.secret.exs` for development instances):
 
 ```shell
-mv config/{generated_config.exs,prod.secret.exs}
+sudo -Hu pleroma mv config/{generated_config.exs,prod.secret.exs}
 ```
 
 * The previous command creates also the file `config/setup_db.psql`, with which you can create the database:
@@ -230,4 +225,4 @@ sudo -Hu pleroma MIX_ENV=prod mix pleroma.user new <username> <your@emailaddress
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/arch_linux_en.md b/docs/installation/arch_linux_en.md
index 7fb69dd60..285743d56 100644
--- a/docs/installation/arch_linux_en.md
+++ b/docs/installation/arch_linux_en.md
@@ -1,4 +1,7 @@
 # Installing on Arch Linux
+
+{! backend/installation/otp_vs_from_source_source.include !}
+
 ## Installation
 
 This guide will assume that you have administrative rights, either as root or a user with [sudo permissions](https://wiki.archlinux.org/index.php/Sudo). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su <username> -s $SHELL -c 'command'` instead.
@@ -10,11 +13,15 @@ This guide will assume that you have administrative rights, either as root or a
 * `git`
 * `base-devel`
 * `cmake`
+* `file`
 
 #### Optional packages used in this guide
 
 * `nginx` (preferred, example configs for other reverse proxies can be found in the repo)
 * `certbot` (or any other ACME client for Let’s Encrypt certificates)
+* `ImageMagick`
+* `ffmpeg`
+* `exiftool`
 
 ### Prepare the system
 
@@ -27,7 +34,7 @@ sudo pacman -Syu
 * Install some of the above mentioned programs:
 
 ```shell
-sudo pacman -S git base-devel elixir cmake
+sudo pacman -S git base-devel elixir cmake file
 ```
 
 ### Install PostgreSQL
@@ -52,6 +59,12 @@ sudo -iu postgres initdb -D /var/lib/postgres/data
 sudo systemctl enable --now postgresql.service
 ```
 
+### Install media / graphics packages (optional, see [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md))
+
+```shell
+sudo pacman -S ffmpeg imagemagick perl-image-exiftool
+```
+
 ### Install PleromaBE
 
 * Add a new system user for the Pleroma service:
@@ -82,7 +95,7 @@ cd /opt/pleroma
 sudo -Hu pleroma mix deps.get
 ```
 
-* Generate the configuration: `sudo -Hu pleroma mix pleroma.instance gen`
+* Generate the configuration: `sudo -Hu pleroma MIX_ENV=prod mix pleroma.instance gen`
   * Answer with `yes` if it asks you to install `rebar3`.
   * This may take some time, because parts of pleroma get compiled first.
   * After that it will ask you a few questions about your instance and generates a configuration file in `config/generated_config.exs`.
@@ -90,7 +103,7 @@ sudo -Hu pleroma mix deps.get
 * Check the configuration and if all looks right, rename it, so Pleroma will load it (`prod.secret.exs` for productive instance, `dev.secret.exs` for development instances):
 
 ```shell
-mv config/{generated_config.exs,prod.secret.exs}
+sudo -Hu pleroma mv config/{generated_config.exs,prod.secret.exs}
 ```
 
 * The previous command creates also the file `config/setup_db.psql`, with which you can create the database:
@@ -205,4 +218,4 @@ sudo -Hu pleroma MIX_ENV=prod mix pleroma.user new <username> <your@emailaddress
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/debian_based_en.md b/docs/installation/debian_based_en.md
index 60c2f47e5..4e52b2155 100644
--- a/docs/installation/debian_based_en.md
+++ b/docs/installation/debian_based_en.md
@@ -1,23 +1,12 @@
 # Installing on Debian Based Distributions
-## Installation
-
-This guide will assume you are on Debian Stretch. This guide should also work with Ubuntu 16.04 and 18.04. It also assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.digitalocean.com/community/tutorials/how-to-add-delete-and-grant-sudo-privileges-to-users-on-a-debian-vps). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su <username> -s $SHELL -c 'command'` instead.
 
-### Required packages
+{! backend/installation/otp_vs_from_source_source.include !}
 
-* `postgresql` (9.6+, Ubuntu 16.04 comes with 9.5, you can get a newer version from [here](https://www.postgresql.org/download/linux/ubuntu/))
-* `postgresql-contrib` (9.6+, same situtation as above)
-* `elixir` (1.8+, Follow the guide to install from the Erlang Solutions repo or use [asdf](https://github.com/asdf-vm/asdf) as the pleroma user)
-* `erlang-dev`
-* `erlang-nox`
-* `git`
-* `build-essential`
-* `cmake`
+## Installation
 
-#### Optional packages used in this guide
+This guide will assume you are on Debian 11 (“bullseye”) or later. This guide should also work with Ubuntu 18.04 (“Bionic Beaver”) and later. It also assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.digitalocean.com/community/tutorials/how-to-add-delete-and-grant-sudo-privileges-to-users-on-a-debian-vps). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su <username> -s $SHELL -c 'command'` instead.
 
-* `nginx` (preferred, example configs for other reverse proxies can be found in the repo)
-* `certbot` (or any other ACME client for Let’s Encrypt certificates)
+{! backend/installation/generic_dependencies.include !}
 
 ### Prepare the system
 
@@ -31,23 +20,23 @@ sudo apt full-upgrade
 * Install some of the above mentioned programs:
 
 ```shell
-sudo apt install git build-essential postgresql postgresql-contrib cmake
+sudo apt install git build-essential postgresql postgresql-contrib cmake libmagic-dev
 ```
 
 ### Install Elixir and Erlang
 
-* Download and add the Erlang repository:
+* Install Elixir and Erlang (you might need to use backports or [asdf](https://github.com/asdf-vm/asdf) on old systems):
 
 ```shell
-wget -P /tmp/ https://packages.erlang-solutions.com/erlang-solutions_2.0_all.deb
-sudo dpkg -i /tmp/erlang-solutions_2.0_all.deb
+sudo apt update
+sudo apt install elixir erlang-dev erlang-nox
 ```
 
-* Install Elixir and Erlang:
+
+### Optional packages: [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md)
 
 ```shell
-sudo apt update
-sudo apt install elixir erlang-dev erlang-nox
+sudo apt install imagemagick ffmpeg libimage-exiftool-perl
 ```
 
 ### Install PleromaBE
@@ -80,7 +69,7 @@ cd /opt/pleroma
 sudo -Hu pleroma mix deps.get
 ```
 
-* Generate the configuration: `sudo -Hu pleroma mix pleroma.instance gen`
+* Generate the configuration: `sudo -Hu pleroma MIX_ENV=prod mix pleroma.instance gen`
   * Answer with `yes` if it asks you to install `rebar3`.
   * This may take some time, because parts of pleroma get compiled first.
   * After that it will ask you a few questions about your instance and generates a configuration file in `config/generated_config.exs`.
@@ -88,9 +77,10 @@ sudo -Hu pleroma mix deps.get
 * Check the configuration and if all looks right, rename it, so Pleroma will load it (`prod.secret.exs` for productive instance, `dev.secret.exs` for development instances):
 
 ```shell
-mv config/{generated_config.exs,prod.secret.exs}
+sudo -Hu pleroma mv config/{generated_config.exs,prod.secret.exs}
 ```
 
+
 * The previous command creates also the file `config/setup_db.psql`, with which you can create the database:
 
 ```shell
@@ -191,4 +181,4 @@ sudo -Hu pleroma MIX_ENV=prod mix pleroma.user new <username> <your@emailaddress
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/debian_based_jp.md b/docs/installation/debian_based_jp.md
index c2dd840d3..3736e857f 100644
--- a/docs/installation/debian_based_jp.md
+++ b/docs/installation/debian_based_jp.md
@@ -17,11 +17,15 @@
 - `git`
 - `build-essential`
 - `cmake`
+- `libmagic-dev`
 
 #### このガイドで利用している追加パッケージ
 
 - `nginx` (おすすめです。他のリバースプロキシを使う場合は、参考となる設定をこのリポジトリから探してください)
 - `certbot` (または何らかのLet's Encrypt向けACMEクライアント)
+- `ImageMagick`
+- `ffmpeg`
+- `exiftool`
 
 ### システムを準備する
 
@@ -33,10 +37,9 @@ sudo apt full-upgrade
 
 * 上記に挙げたパッケージをインストールしておきます。
 ```
-sudo apt install git build-essential postgresql postgresql-contrib cmake
+sudo apt install git build-essential postgresql postgresql-contrib cmake ffmpeg imagemagick libmagic-dev
 ```
 
-
 ### ElixirとErlangをインストールします
 
 * Erlangのリポジトリをダウンロードおよびインストールします。
@@ -51,6 +54,12 @@ sudo apt update
 sudo apt install elixir erlang-dev erlang-nox
 ```
 
+### オプションパッケージ: [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md)
+
+```shell
+sudo apt install imagemagick ffmpeg libimage-exiftool-perl
+```
+
 ### Pleroma BE (バックエンド) をインストールします
 
 *  Pleroma用に新しいユーザーを作ります。
@@ -80,7 +89,7 @@ sudo -Hu pleroma mix deps.get
 
 * コンフィギュレーションを生成します。
 ```
-sudo -Hu pleroma mix pleroma.instance gen
+sudo -Hu pleroma MIX_ENV=prod mix pleroma.instance gen
 ```
     * rebar3をインストールしてもよいか聞かれたら、yesを入力してください。
     * このときにpleromaの一部がコンパイルされるため、この処理には時間がかかります。
@@ -89,12 +98,12 @@ sudo -Hu pleroma mix pleroma.instance gen
 
 * コンフィギュレーションを確認して、もし問題なければ、ファイル名を変更してください。
 ```
-mv config/{generated_config.exs,prod.secret.exs}
+sudo -Hu pleroma mv config/{generated_config.exs,prod.secret.exs}
 ```
 
 * 先程のコマンドで、すでに `config/setup_db.psql` というファイルが作られています。このファイルをもとに、データベースを作成します。
 ```
-sudo -Hu pleroma mix pleroma.instance gen
+sudo -Hu pleroma MIX_ENV=prod mix pleroma.instance gen
 ```
 
 * そして、データベースのマイグレーションを実行します。
@@ -182,5 +191,5 @@ sudo -Hu pleroma MIX_ENV=prod mix pleroma.user new <username> <your@emailaddress
 
 インストールについて質問がある、もしくは、うまくいかないときは、以下のところで質問できます。
 
-* [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org)
-* **Freenode** の **#pleroma** IRCチャンネル
+* [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat)
+* **libera.chat** の **#pleroma** IRCチャンネル
diff --git a/docs/installation/freebsd_en.md b/docs/installation/freebsd_en.md
index ca2575d9b..9cbe0f203 100644
--- a/docs/installation/freebsd_en.md
+++ b/docs/installation/freebsd_en.md
@@ -1,8 +1,10 @@
-# Installing on FreeBSD 
+# Installing on FreeBSD
 
 This document was written for FreeBSD 12.1, but should be work on future releases.
 
-## Required software 
+{! backend/installation/generic_dependencies.include !}
+
+## Installing software used in this guide
 
 This assumes the target system has `pkg(8)`.
 
@@ -26,6 +28,12 @@ Setup the required services to automatically start at boot, using `sysrc(8)`.
 # service postgresql start
 ```
 
+### Install media / graphics packages (optional, see [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md))
+
+```shell
+# pkg install imagemagick ffmpeg p5-Image-ExifTool
+```
+
 ## Configuring Pleroma
 
 Create a user for Pleroma:
@@ -48,7 +56,7 @@ Configure Pleroma. Note that you need a domain name at this point:
 ```
 $ cd /home/pleroma/pleroma
 $ mix deps.get # Enter "y" when asked to install Hex
-$ mix pleroma.instance gen # You will be asked a few questions here.
+$ MIX_ENV=prod mix pleroma.instance gen # You will be asked a few questions here.
 $ cp config/generated_config.exs config/prod.secret.exs
 ```
 
@@ -207,4 +215,4 @@ incorrect timestamps. You should have ntpd running.
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/generic_dependencies.include b/docs/installation/generic_dependencies.include
new file mode 100644
index 000000000..2dbd93e42
--- /dev/null
+++ b/docs/installation/generic_dependencies.include
@@ -0,0 +1,16 @@
+## Required dependencies
+
+* PostgreSQL 9.6+
+* Elixir 1.9+
+* Erlang OTP 22.2+
+* git
+* file / libmagic
+* gcc (clang might also work)
+* GNU make
+* CMake
+
+## Optional dependencies
+
+* ImageMagick
+* FFmpeg
+* exiftool
diff --git a/docs/installation/gentoo_en.md b/docs/installation/gentoo_en.md
index 5a676380c..36882c8c8 100644
--- a/docs/installation/gentoo_en.md
+++ b/docs/installation/gentoo_en.md
@@ -1,11 +1,12 @@
 # Installing on Gentoo GNU/Linux
+
+{! backend/installation/otp_vs_from_source_source.include !}
+
 ## Installation
 
 This guide will assume that you have administrative rights, either as root or a user with [sudo permissions](https://wiki.gentoo.org/wiki/Sudo). Lines that begin with `#` indicate that they should be run as the superuser. Lines using `$` should be run as the indicated user, e.g. `pleroma$` should be run as the `pleroma` user.
 
-### Configuring your hostname (optional)
-
-If you would like your prompt to permanently include your host/domain, change `/etc/conf.d/hostname` to your hostname. You can reboot or use the `hostname` command to make immediate changes.
+{! backend/installation/generic_dependencies.include !}
 
 ### Your make.conf, package.use, and USE flags
 
@@ -29,12 +30,16 @@ Gentoo quite pointedly does not come with a cron daemon installed, and as such i
 * `dev-lang/elixir`
 * `dev-vcs/git`
 * `dev-util/cmake`
+* `sys-apps/file`
 
 #### Optional ebuilds used in this guide
 
 * `www-servers/nginx` (preferred, example configs for other reverse proxies can be found in the repo)
 * `app-crypt/certbot` (or any other ACME client for Let’s Encrypt certificates)
 * `app-crypt/certbot-nginx` (nginx certbot plugin that allows use of the all-powerful `--nginx` flag on certbot)
+* `media-gfx/imagemagick`
+* `media-video/ffmpeg`
+* `media-libs/exiftool`
 
 ### Prepare the system
 
@@ -47,10 +52,10 @@ Gentoo quite pointedly does not come with a cron daemon installed, and as such i
 * Emerge all required the required and suggested software in one go:
 
 ```shell
- # emerge --ask dev-db/postgresql dev-lang/elixir dev-vcs/git www-servers/nginx app-crypt/certbot app-crypt/certbot-nginx dev-util/cmake
+ # emerge --ask dev-db/postgresql dev-lang/elixir dev-vcs/git www-servers/nginx app-crypt/certbot app-crypt/certbot-nginx dev-util/cmake sys-apps/file
 ```
 
-If you would not like to install the optional packages, remove them from this line. 
+If you would not like to install the optional packages, remove them from this line.
 
 If you're running this from a low-powered virtual machine, it should work though it will take some time. There were no issues on a VPS with a single core and 1GB of RAM; if you are using an even more limited device and run into issues, you can try creating a swapfile or use a more powerful machine running Gentoo to [cross build](https://wiki.gentoo.org/wiki/Cross_build_environment). If you have a wait ahead of you, now would be a good time to take a break, strech a bit, refresh your beverage of choice and/or get a snack, and reply to Arch users' posts with "I use Gentoo btw" as we do.
 
@@ -75,18 +80,24 @@ The output from emerging postgresql should give you a command for initializing t
 ```
 
 * Start postgres and enable the system service
- 
+
 ```shell
  # /etc/init.d/postgresql-11 start
  # rc-update add postgresql-11 default
  ```
- 
+
 ### A note on licenses, the AGPL, and deployment procedures
 
 If you do not plan to make any modifications to your Pleroma instance, cloning directly from the main repo will get you what you need. However, if you plan on doing any contributions to upstream development, making changes or modifications to your instance, making custom themes, or want to play around--and let's be honest here, if you're using Gentoo that is most likely you--you will save yourself a lot of headache later if you take the time right now to fork the Pleroma repo and use that in the following section.
 
 Not only does this make it much easier to deploy changes you make, as you can commit and pull from upstream and all that good stuff from the comfort of your local machine then simply `git pull` on your instance server when you're ready to deploy, it also ensures you are compliant with the Affero General Public Licence that Pleroma is licenced under, which stipulates that all network services provided with modified AGPL code must publish their changes on a publicly available internet service and for free. It also makes it much easier to ask for help from and provide help to your fellow Pleroma admins if your public repo always reflects what you are running because it is part of your deployment procedure.
 
+### Install media / graphics packages (optional, see [`docs/installation/optional/media_graphics_packages.md`](docs/installation/optional/media_graphics_packages.md))
+
+```shell
+# emerge --ask media-video/ffmpeg media-gfx/imagemagick media-libs/exiftool
+```
+
 ### Install PleromaBE
 
 * Add a new system user for the Pleroma service and set up default directories:
@@ -125,7 +136,7 @@ pleroma$ mix deps.get
 * Generate the configuration:
 
 ```shell
-pleroma$ mix pleroma.instance gen
+pleroma$ MIX_ENV=prod mix pleroma.instance gen
 ```
 
   * Answer with `yes` if it asks you to install `rebar3`.
@@ -231,7 +242,7 @@ First, ensure that the command you will be installing into your crontab works.
  # /usr/bin/certbot renew --nginx
 ```
 
-Assuming not much time has passed since you got certbot working a few steps ago, you should get a message for all domains you installed certificates for saying `Cert not yet due for renewal`. 
+Assuming not much time has passed since you got certbot working a few steps ago, you should get a message for all domains you installed certificates for saying `Cert not yet due for renewal`.
 
 Now, run crontab as a superuser with `crontab -e` or `sudo crontab -e` as appropriate, and add the following line to your cron:
 
@@ -288,4 +299,4 @@ If you opted to allow sudo for the `pleroma` user but would like to remove the a
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/migrating_from_source_otp_en.md b/docs/installation/migrating_from_source_otp_en.md
index d303a6daf..e4a01d8db 100644
--- a/docs/installation/migrating_from_source_otp_en.md
+++ b/docs/installation/migrating_from_source_otp_en.md
@@ -1,7 +1,8 @@
 # Switching a from-source install to OTP releases
 
-## What are OTP releases?
-OTP releases are as close as you can get to binary releases with Erlang/Elixir. The release is self-contained, and provides everything needed to boot it, it is easily administered via the provided shell script to open up a remote console, start/stop/restart the release, start in the background, send remote commands, and more.
+{! backend/installation/otp_vs_from_source.include !}
+
+In this guide we cover how you can migrate from a from source installation to one using OTP releases.
 
 ## Pre-requisites
 You will be running commands as root. If you aren't root already, please elevate your priviledges by executing `sudo su`/`su`.
diff --git a/docs/installation/netbsd_en.md b/docs/installation/netbsd_en.md
index 6ad0de2f6..41b3b0072 100644
--- a/docs/installation/netbsd_en.md
+++ b/docs/installation/netbsd_en.md
@@ -1,6 +1,8 @@
 # Installing on NetBSD
 
-## Required software 
+{! backend/installation/generic_dependencies.include !}
+
+## Installing software used in this guide
 
 pkgin should have been installed by the NetBSD installer if you selected
 the right options. If it isn't installed, install it using pkg_add.
@@ -10,7 +12,7 @@ Pleroma uses.
 
 The `mksh` shell is needed to run the Elixir `mix` script.
 
-`# pkgin install acmesh elixir git-base git-docs mksh nginx postgresql11-server postgresql11-client postgresql11-contrib sudo`
+`# pkgin install acmesh elixir git-base git-docs mksh nginx postgresql11-server postgresql11-client postgresql11-contrib sudo ffmpeg4 ImageMagick`
 
 You can also build these packages using pkgsrc:
 ```
@@ -44,6 +46,10 @@ pgsql=YES
 
 First, run `# /etc/rc.d/pgsql start`. Then, `$ sudo -Hu pgsql -g pgsql createdb`.
 
+### Install media / graphics packages (optional, see [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md))
+
+`# pkgin install ImageMagick ffmpeg4 p5-Image-ExifTool`
+
 ## Configuring Pleroma
 
 Create a user for Pleroma:
@@ -67,7 +73,7 @@ Configure Pleroma. Note that you need a domain name at this point:
 ```
 $ cd /home/pleroma/pleroma
 $ mix deps.get
-$ mix pleroma.instance gen # You will be asked a few questions here.
+$ MIX_ENV=prod mix pleroma.instance gen # You will be asked a few questions here.
 ```
 
 Since Postgres is configured, we can now initialize the database. There should
@@ -189,8 +195,6 @@ Run `# /etc/rc.d/pleroma start` to start Pleroma.
 
 Restart nginx with `# /etc/rc.d/nginx restart` and you should be up and running.
 
-If you need further help, contact niaa on freenode.
-
 Make sure your time is in sync, or other instances will receive your posts with
 incorrect timestamps. You should have ntpd running.
 
@@ -204,4 +208,4 @@ incorrect timestamps. You should have ntpd running.
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/openbsd_en.md b/docs/installation/openbsd_en.md
index eee452845..c80c8f678 100644
--- a/docs/installation/openbsd_en.md
+++ b/docs/installation/openbsd_en.md
@@ -4,26 +4,32 @@ This guide describes the installation and configuration of pleroma (and the requ
 
 For any additional information regarding commands and configuration files mentioned here, check the man pages [online](https://man.openbsd.org/) or directly on your server with the man command.
 
-#### Required software
-
-The following packages need to be installed:
+{! backend/installation/generic_dependencies.include !}
 
-  * elixir
-  * gmake
-  * ImageMagick
-  * git
-  * postgresql-server
-  * postgresql-contrib
-  * cmake
+### Preparing the system
+#### Required software
 
 To install them, run the following command (with doas or as root):
 
 ```
-pkg_add elixir gmake ImageMagick git postgresql-server postgresql-contrib cmake
+pkg_add elixir gmake git postgresql-server postgresql-contrib cmake ffmpeg ImageMagick
 ```
 
 Pleroma requires a reverse proxy, OpenBSD has relayd in base (and is used in this guide) and packages/ports are available for nginx (www/nginx) and apache (www/apache-httpd). Independently of the reverse proxy, [acme-client(1)](https://man.openbsd.org/acme-client) can be used to get a certificate from Let's Encrypt.
 
+#### Optional software
+
+Per [`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md):
+  * ImageMagick
+  * ffmpeg
+  * exiftool
+
+To install the above:
+
+```
+pkg_add ImageMagick ffmpeg p5-Image-ExifTool
+```
+
 #### Creating the pleroma user
 Pleroma will be run by a dedicated user, \_pleroma. Before creating it, insert the following lines in login.conf:
 ```
@@ -225,7 +231,7 @@ Enter a shell as \_pleroma (as root `su _pleroma -`) and enter pleroma's install
 Then follow the main installation guide:
 
   * run `mix deps.get`
-  * run `mix pleroma.instance gen` and enter your instance's information when asked
+  * run `MIX_ENV=prod mix pleroma.instance gen` and enter your instance's information when asked
   * copy config/generated\_config.exs to config/prod.secret.exs. The default values should be sufficient but you should edit it and check that everything seems OK.
   * exit your current shell back to a root one and run `psql -U postgres -f /home/_pleroma/pleroma/config/setup_db.psql` to setup the database.
   * return to a \_pleroma shell into pleroma's installation directory (`su _pleroma -;cd ~/pleroma`) and run `MIX_ENV=prod mix ecto.migrate`
@@ -250,4 +256,4 @@ LC_ALL=en_US.UTF-8 MIX_ENV=prod mix pleroma.user new <username> <your@emailaddre
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.
diff --git a/docs/installation/openbsd_fi.md b/docs/installation/openbsd_fi.md
index b5b5056a9..3c40b2d1a 100644
--- a/docs/installation/openbsd_fi.md
+++ b/docs/installation/openbsd_fi.md
@@ -10,13 +10,24 @@ suositeltavaa tehdä komennon `doas` avulla, katso `doas (1)` ja `doas.conf (5)`
 Tästä eteenpäin oletuksena on, että domain "esimerkki.com" osoittaa
 serverin IP-osoitteeseen.
 
-Jos asennuksen kanssa on ongelmia, IRC-kanava #pleroma Freenodessa tai
-Matrix-kanava #freenode_#pleroma:matrix.org ovat hyviä paikkoja löytää apua
+Jos asennuksen kanssa on ongelmia, IRC-kanava #pleroma Libera.chat tai
+Matrix-kanava #pleroma:libera.chat ovat hyviä paikkoja löytää apua
 (englanniksi), `/msg eal kukkuu` jos haluat välttämättä puhua härmää.
 
 Asenna tarvittava ohjelmisto:
 
-`# pkg_add git elixir gmake postgresql-server-10.3 postgresql-contrib-10.3 cmake`
+`# pkg_add git elixir gmake postgresql-server-10.3 postgresql-contrib-10.3 cmake ffmpeg ImageMagick`
+
+#### Optional software
+
+[`docs/installation/optional/media_graphics_packages.md`](../installation/optional/media_graphics_packages.md):
+  * ImageMagick
+  * ffmpeg
+  * exiftool
+
+Asenna tarvittava ohjelmisto:
+
+`# pkg_add ImageMagick ffmpeg p5-Image-ExifTool`
 
 Luo postgresql-tietokanta:
 
diff --git a/docs/installation/optional/media_graphics_packages.md b/docs/installation/optional/media_graphics_packages.md
new file mode 100644
index 000000000..cb3d71188
--- /dev/null
+++ b/docs/installation/optional/media_graphics_packages.md
@@ -0,0 +1,32 @@
+# Optional software packages needed for specific functionality
+
+For specific Pleroma functionality (which is disabled by default) some or all of the below packages are required:
+  * `ImageMagic`
+  * `ffmpeg`
+  * `exiftool`
+  
+Please refer to documentation in `docs/installation` on how to install them on specific OS.
+  
+Note: the packages are not required with the current default settings of Pleroma.
+
+## `ImageMagick`
+
+`ImageMagick` is a set of tools to create, edit, compose, or convert bitmap images.
+
+It is required for the following Pleroma features:
+  * `Pleroma.Upload.Filters.Mogrify`, `Pleroma.Upload.Filters.Mogrifun` upload filters (related config: `Plaroma.Upload/filters` in `config/config.exs`)
+  * Media preview proxy for still images (related config: `media_preview_proxy/enabled` in `config/config.exs`)
+  
+## `ffmpeg`
+
+`ffmpeg` is software to record, convert and stream audio and video.
+
+It is required for the following Pleroma features:
+  * Media preview proxy for videos (related config: `media_preview_proxy/enabled` in `config/config.exs`)
+
+## `exiftool`
+
+`exiftool` is media files metadata reader/writer.
+
+It is required for the following Pleroma features:
+  * `Pleroma.Upload.Filters.Exiftool` upload filter (related config: `Plaroma.Upload/filters` in `config/config.exs`)
diff --git a/docs/installation/otp_en.md b/docs/installation/otp_en.md
index b7e3bb2ac..0861a8157 100644
--- a/docs/installation/otp_en.md
+++ b/docs/installation/otp_en.md
@@ -1,5 +1,9 @@
 # Installing on Linux using OTP releases
 
+{! backend/installation/otp_vs_from_source.include !}
+
+This guide covers a installation using an OTP release. To install Pleroma from source, please check out the corresponding guide for your distro.
+
 ## Pre-requisites
 * A machine running Linux with GNU (e.g. Debian, Ubuntu) or musl (e.g. Alpine) libc and `x86_64`, `aarch64` or `armv7l` CPU, you have root access to. If you are not sure if it's compatible see [Detecting flavour section](#detecting-flavour) below
 * A (sub)domain pointed to the machine
@@ -27,17 +31,36 @@ Other than things bundled in the OTP release Pleroma depends on:
 * PostgreSQL (also utilizes extensions in postgresql-contrib)
 * nginx (could be swapped with another reverse proxy but this guide covers only it)
 * certbot (for Let's Encrypt certificates, could be swapped with another ACME client, but this guide covers only it)
+* libmagic/file
+
+=== "Alpine"
+    ```
+    awk 'NR==2' /etc/apk/repositories | sed 's/main/community/' | tee -a /etc/apk/repositories
+    apk update
+    apk add curl unzip ncurses postgresql postgresql-contrib nginx certbot file-dev
+    ```
+
+=== "Debian/Ubuntu"
+    ```
+    apt install curl unzip libncurses5 postgresql postgresql-contrib nginx certbot libmagic-dev
+    ```
+
+### Installing optional packages
+
+Per [`docs/installation/optional/media_graphics_packages.md`](optional/media_graphics_packages.md):
+  * ImageMagick
+  * ffmpeg
+  * exiftool
 
 === "Alpine"
     ```
-    echo "http://nl.alpinelinux.org/alpine/latest-stable/community" >> /etc/apk/repositories
     apk update
-    apk add curl unzip ncurses postgresql postgresql-contrib nginx certbot
+    apk add imagemagick ffmpeg exiftool
     ```
 
 === "Debian/Ubuntu"
     ```
-    apt install curl unzip libncurses5 postgresql postgresql-contrib nginx certbot
+    apt install imagemagick ffmpeg libimage-exiftool-perl
     ```
 
 ## Setup
@@ -69,6 +92,8 @@ RUM indexes are an alternative indexing scheme that is not included in PostgreSQ
 #### (Optional) Performance configuration
 It is encouraged to check [Optimizing your PostgreSQL performance](../configuration/postgresql.md) document, for tips on PostgreSQL tuning.
 
+Restart PostgreSQL to apply configuration changes:
+
 === "Alpine"
     ```
     rc-service postgresql restart
@@ -79,15 +104,6 @@ It is encouraged to check [Optimizing your PostgreSQL performance](../configurat
     systemctl restart postgresql
     ```
 
-If you are using PostgreSQL 12 or higher, add this to your Ecto database configuration
-
-```elixir
-prepare: :named,
-parameters: [
-  plan_cache_mode: "force_custom_plan"
-]
-```
-
 ### Installing Pleroma
 ```sh
 # Create a Pleroma user
@@ -219,7 +235,7 @@ At this point if you open your (sub)domain in a browser you should see a 502 err
 
 If everything worked, you should see Pleroma-FE when visiting your domain. If that didn't happen, try reviewing the installation steps, starting Pleroma in the foreground and seeing if there are any errrors.
 
-Still doesn't work? Feel free to contact us on [#pleroma on freenode](https://irc.pleroma.social) or via matrix at <https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org>, you can also [file an issue on our Gitlab](https://git.pleroma.social/pleroma/pleroma-support/issues/new)
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC, you can also [file an issue on our Gitlab](https://git.pleroma.social/pleroma/pleroma-support/issues/new).
 
 ## Post installation
 
@@ -277,7 +293,7 @@ nginx -t
 
 ## Create your first user and set as admin
 ```sh
-cd /opt/pleroma/bin
+cd /opt/pleroma
 su pleroma -s $SHELL -lc "./bin/pleroma_ctl user new joeuser joeuser@sld.tld --admin"
 ```
 This will create an account withe the username of 'joeuser' with the email address of joeuser@sld.tld, and set that user's account as an admin. This will result in a link that you can paste into the browser, which logs you in and enables you to set the password.
@@ -288,5 +304,4 @@ This will create an account withe the username of 'joeuser' with the email addre
 
 ## Questions
 
-Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.
-
+Questions about the installation or didn’t it work as it should be, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC, you can also [file an issue on our Gitlab](https://git.pleroma.social/pleroma/pleroma-support/issues/new).
diff --git a/docs/installation/otp_vs_from_source.include b/docs/installation/otp_vs_from_source.include
new file mode 100644
index 000000000..63e837a53
--- /dev/null
+++ b/docs/installation/otp_vs_from_source.include
@@ -0,0 +1,3 @@
+## OTP releases vs from-source installations
+
+There are two ways to install Pleroma. You can use OTP releases or do a from-source installation. OTP releases are as close as you can get to binary releases with Erlang/Elixir. The release is self-contained, and provides everything needed to boot it, it is easily administered via the provided shell script to open up a remote console, start/stop/restart the release, start in the background, send remote commands, and more. With from source installations you install Pleroma from source, meaning you have to install certain dependencies like Erlang+Elixir and compile Pleroma yourself.
diff --git a/docs/installation/otp_vs_from_source_source.include b/docs/installation/otp_vs_from_source_source.include
new file mode 100644
index 000000000..63482b69d
--- /dev/null
+++ b/docs/installation/otp_vs_from_source_source.include
@@ -0,0 +1,3 @@
+{! backend/installation/otp_vs_from_source.include !}
+
+This guide covers a from-source installation. To install using OTP releases, please check out [the OTP guide](./otp_en.md).
diff --git a/docs/installation/yunohost_en.md b/docs/installation/yunohost_en.md
new file mode 100644
index 000000000..4c34e85d5
--- /dev/null
+++ b/docs/installation/yunohost_en.md
@@ -0,0 +1,9 @@
+# Installing on Yunohost
+
+[YunoHost](https://yunohost.org) is a server operating system aimed at self-hosting. The YunoHost community maintains a package of Pleroma which allows you to install Pleroma on YunoHost. You can install it via the normal way through the admin web interface, or through the CLI. More information can be found at [the repo of the package](https://github.com/YunoHost-Apps/pleroma_ynh).
+
+## Questions
+
+Questions and problems related to the YunoHost parts can be done through the [regular YunoHost channels](https://yunohost.org/en/help).
+
+For questions about Pleroma, ask in [#pleroma:libera.chat](https://matrix.to/#/#pleroma:libera.chat) via Matrix or **#pleroma** on **libera.chat** via IRC.