ICONS: Add README and TOC

README.md

@@ -1,2 +1,22 @@
-# scummvm-icons
-Icons repository for ScummVM rich presence
+# ScummVM Game Icons
+
+This repository contains icons of [ScummVM-supported games](https://www.scummvm.org/compatibility/) for features like:
+
+- Discord rich presence
+- Taskbar integration
+
+Or just plain old shortcuts.
+
+## Contributing
+
+Check the [Table of Contents](TOC.md) to see what icons we're missing. This covers every possible ScummVM game, so prioritize mainstream titles over every edition and tech demo.
+
+Just send us a pull request with new icons, or open an issue if Git's not your thing (you can attach files to issues via drag'n'drop). Be sure to update the TOC when you do.
+
+Icons should follow this format:
+
+- PNG format with alpha transparency.
+- 512x512 size.
+- `<engine>_<game>.png` filename.
+
+Variants of the same game can have the same icon. For engines with lots of games (eg. Wintermute, Glk) it might be better to have a generic `<engine>.png` icon to cover all the games.