I've managed to produce a file that's a valid GB ROM (tested on my GB Pocket) and a valid PNG image.
Rules: Only RST $28, $30, and $38 may be used, not $00-$20, and $28 must start with LD L,L. There must also be enough free space at the end of the ROM to hold the PNG.
Attachment:
File comment: This is a ROM.
gbpng.gb.png [ 32 KiB | Viewed 4080 times ]
gbpng.gb.png [ 32 KiB | Viewed 4080 times ]
Rules: Only RST $28, $30, and $38 may be used, not $00-$20, and $28 must start with LD L,L. There must also be enough free space at the end of the ROM to hold the PNG.