My gamerpicture is from the Rumble Roses XX Heel Picture Pack. It's Candy Cane from the game. You can actually see where anybody's gamerpic is from on Xbox.com by going to their profile and moving your mouse cursor over their gamerpic.
UNLESS you were referring to my Gamerpicture on this site. If that's the case, it's from Gunstar Super Heroes for the Game Boy Advance.