Good question! If there is nothing else visible in a scene (no text, visible actors, etc) except for the background, you can get away with displaying up to about 255 unique tiles, which most GB camera photos fall under. A way to cut down on extra tiles in GB camera photos is to make sure the border around the photo is blank (this usually saves around 30)! This had to be done to make some of the photos in the gallery display properly. Hope this helps!