Thanks! PNG import is mainly intended for pulling PETSCII content into Petmate from running .prg files in VICE. The pixel data and image dimensions need to match exactly for the import to succeed. I try to explain it in the docs but the feature just kinda doesn’t do what most people expect it to.
Petmate author here. Doesn’t notarization require an Apple Developer ID? Out of principle, I don’t want to pay Apple 100 USD a year just to build my free app.
I also used some Haskell in another C64 project. Made a VICE memory snapshot parser for digging some values out of RAM. Haskell was a lot handier for byte level access than Python.