Rip them up or burn them. If any future girlfriends find them it'll only mean trouble. Especially the lovey-dovey photos. Memories are kept in your brain, photos are not memories they are only triggers for memories so keep the photos that remind you of that time in your life, but get rid of the ones where she's in them.
If future girlfriends find them they will do the following;
1) Compare looks
2) Compare happiness
3) See your "type" and question you about it
Oh, and the 3 points I just mentioned aren't even for cRaZy girlfriends, they are just for women in general.