merk, i'm trying to keep up with your edits, here... the most-recent omitted the attachment(s).
from what i did download (the HUGE project file), i have to ask if you have the rights to distribute the graphics inside? meanwhile, multiple 3000x3000 images for a simple sprite is overkill...
otherwise, it looked like you had reduced the huge project down to a small example of your issue at some point? if you respond here with that BASIC example (vs the bloated spaghetti-project), i'm sure someone would have some advice.
and, now ANOTHER edit while i was posting this...