I was having some trouble with building a project tiny app when using sprite atlases. In case anyone runs into some issues with atlas here are some tips. 1) Make sure at least one sprite is referenced in a component from the sprite atlas. See https://forum.unity.com/threads/solved-sprite-atlas-with-unity-tiny.646957/ 2) Don't use variants! Just don't. Even if you don't include it in the build, they are still included in the packing process, creating duplicates. 3) Make sure your sprite atlases only produce one image per atlas. Project tiny will not be able to find the other images. Just split up your assets and make more atlases instead.