Mega Man Zero Collection Cheats :
Code - Gallery Unlockables
To unlock pictures and Mod Cards in the gallery, finish the games in both Title Select and Easy Scenario modes. Wallpapers can only be unlocked from Title Select and only from the earliest game they appear in (i.e. you can not unlock the Z-Buster or Z-Saber Wallpapers by viewing them in Zero 4, only in Zero 1).