I think what you are looking for is here. Seems like a very simple and convenient workflow for what you are trying to do. I've tried it and it works nicely.
http://www.mac-forums.com/forums/im...-app-how-cycle-through-all-photos-folder.html
http://www.mac-forums.com/forums/im...-app-how-cycle-through-all-photos-folder.html