I think that is the main galley apk ill explain sorry when you press menu button then click wallpaper to change your wallpaper you have 3 basic option (more if you have added themes or other apps that will appear there) 1. gallery that will take you to your main picture gallery 2. live wallpapers thst will take you to your live wallpapers to choose from 3. wallpaper gallery in most custom ROMs that will take you to a lil photo slide show of just two photos one which is black but in the stock official 2.2 or 2.3 ROMs there is a large slide of photos to choose from i want those photos .....
I have attached pitures but cause i am using a ustom ROM you can only see the two photos i mentioned above but it should show what i mean
: Nexus 4
: Paronoidroid 3.0
: Franco Kernel nightly 83
: Nexus 7
: LGp500, HTC Sensation, Moto Xoom, Galaxy Nexus
PS if i help you press the thank you button it makes me feel all warm inside