Minecraft wiki entry for Creating_resource_pack_add-ons, associated text: Minecraft supports .tgas, .pngs and .jpgs. However, it will first try to load the TGA version, then the png, then the jpg. This means if you have 2 creeper textures, one as a png, and one as a TGA, the game will see the TGA one first and load that as your creeper’s texture.