Currently Being ModeratedDec 9, 2012 12:13 AM (in response to RickFracassa)
Photos that are the same in diiferent folders are not duplicated. It's only a link to the original. You will notice that if you delete the photos in Camera Roll, the same photos will be deleted in every folder.
To solve this, connect and save the photos to computer and in iTunes select the photos you want and sync back to the iPhone.