Sadly I’m really late for bed and don’t have time to test this on the Game Frame, but it should work. REALLY nice work, DM. Very clever.
In Photoshop I just went FILE -> SCRIPTS -> EXPORT LAYERS AS FILES.
In IRFANVIEW (a free PC app) I went FILE -> BATCH CONVERSION, added all of the files output from Photoshop, sorted them by name (descending), and output as 24-bit BMP using the Name pattern “#”. No quotes, obviously.
I agree there needs to be a smoother process — ideally some kind of cross platform front end to imagemagick — but this process has worked well for me so far.