Added some info

CONTRIBUTING.md

@@ -6,7 +6,7 @@ Join #realm.one on Freenode if you want to chat!
 ## Map creation
 Artwork comes from [OpenGameArt.org](https://opengameart.org/content/tiny-16-basic).
 
-Maps are assembled from sprites using the ["Tiled" map editor](https://www.mapeditor.org/). Which yields `.tmx` files we can then parse in rust using the [rs-tiledcrate](https://github.com/mattyhall/rs-tiled).
+Maps are assembled from sprites using the ["Tiled" map editor](https://www.mapeditor.org/). Which yields `.tmx` files we can then parse in rust using the [rs-tiledcrate](https://github.com/mattyhall/rs-tiled). Tiles are combined into one massive tileset using TexturePacker, this tileset is called master16.png
 
 ## Keybindings
 The keybindings are described in the `resources/bindings.ron` file. You also need to create the proper enum variants in `src/key_bindings.rs` for our game to be able to parse the file properly.