Last time when I was making mobile game, advanced minification was not working (although simple minification was working). With advanced minification,the app used to get freezed at the starting itself.
Advanced Minification can be sometimes resource consuming especially for older computers. (I think my old computer used to get really slow during these processes a few years ago)
Do you get any error message popup which says "Advanced minify failed, please check console" or something like that?
Also, when I load image from files folder in Sprite, no idea why, sometimes randomly the images gets zoomed so much that it looks blurry. It happens 9:1
Might happen because of your "Size" parameter.