If you are talking about Gallery the abysmal Android photo viewing app-attempt, I wouldn't lump that in with your list of impressive technical achievements. I hope you are referring to the web album builder or something else.
http://en.wikipedia.org/wiki/Gallery_Project
To my knowledge, the Android photo viewing app isn't open-source (and I'm kinda surprised that alternatives to some of the default Android apps haven't popped up - the Gallery and Music Player apps really kinda suck.)