There are two sources for graphics this game uses. The graphics used for rendering the game state (e.g. tiles, units) are part of the texture atlas (see android/assets/textures.png). The skin (see android/assets/skin) contains most UI graphics.

All custom graphics were created with GIMP. The project files as well as exported png graphics reside in /graphics. After changing or adding graphics, the texture atlas needs to be updated. This is done using the GDX texture packer. The project file with the needed settings can be found in /graphics. The source and output paths may need to be adjusted to your setup.