@branch300bpm oh, but you lose information in doing it that way, unless you make each frame of an animation its own file with a naming convention for the metadata. I'm labeling and commenting the sprites in an animation sequence with the sprite name, frame number, and shared colors needed to render it.
I can't think of a good way to deal with all that metadata in a .prg, since we don't have comments or labels anymore, once it's binary.