Hard to say since I know nothing of the situation.. but in general:
Deleting the pictures won't erase the cause of your pain. Looking at them might make it worse, so hide them somewhere in the depths of your harddrive... but one day, when it doesn't hurt so much, you might regret destroying them. I've kept pictures of ex's that I wanted to tear up or burn at one point... but years later, they're nice to have, as sort of keepsakes of the good times, or something.
I had a dream about that same girl that I worked with at the book store, 2 years ago, last night. I would love to be her bf if she wasnt already in love with someone else, she loves/ loved him too much from las I saw her 2 years ago, geeze they could be married by now for all I know