It takes 10 2x2 inch photos and 2 2x4inch photos. I have used faces although I feel that holiday snaps would probably look better (you're not chopping anyone in half then!) There will be acetate overlays to use though so you can actually see your cutting lines before you start to cut you photographs up. I also would suggest using copies/home print outs rather than originals ~ just in case!
Also this Friday and Saturday the shop has space downstairs in the shopping centre, so pop along and see what we're all making and getting up to!