help on gba emulators

Every time I download a gba emulator and run it, it will say I need a gba bios image.
what is a bios image and where do I get one.

just download this one...it has the bios file and everything included so just put your roms in and play.

[Link Removed]
DA

[ace]

staxx....gba bios is illegal...
sebass- It's the gba bios, just search torrent sites for "gba bios" or something like that. That's what the gba image is. Also make sure your using gpSP 0.9

ahhh i see, now i know