Place SG-1000 preview images in "sg1000/media/mixrbv2".
pFBN, as fbneo, support consoles roms. Here is the corresponding folders where roms should be located (as fbneo):
Arcade : "roms"
Channel F : "channelf"
Coleco : "coleco"
Nintendo NES FDS : "fds"
Sega GameGear : "gamegear"
Sega MegaDrive : "megadrive"
MSX : "msx"
Nintendo NES : "nes"
Neo Geo Pocket : "ngp"
Nec PC-Engine : "pce"
SG-1000 : "sg1000"
Nec SuperGraFX : "sgx"
Sega Master System : "sms"
Spectrum : "spectrum"
Nec TurboGraFX-16 : "tg16"