ACADE-roms/acade/roms
PNG-roms/acade/snap

GBA-roms/gbaroms/roms
PNG-roms/gbaroms/screenshots

MD-
roms/mdroms/roms
PNG-
roms/mdroms/screenshots

N64-
roms/n64roms/roms
PNG-
roms/n64roms/screenshots

NES-roms/nesroms/roms
PNG-roms/nesroms/screenshots

PS-roms/psroms/roms
PNG-roms/psroms/screenshots
if you store Emulator Game in SD Card, just create files like above.