WeSpot is a game for iPhone in which you spot the differences between two images that aren't quite the same. It is available from both the weiPhone (app.weiphone.com/installer) and iPhone Cake (iphonecake.com/src/all) repos.
I added more levels via Installer, so they may be different for you. I'm not really sure which originally came with the game.
Level 1:

Level 2:

Level 3:

Level 4:

Level 5:

Level 6:

Level 7:

Level 8:

Level 9:

Level 10:

Level 11:

Level 12:

Level 13:

Level 14:

Level 15:

I'll be posting more of the levels later.