Well first of all, I really think that you need to ask your girlfriend outright about the pictures. I too doubt that they were taken by a woman, and if you are in a pretty serious relationship, I think that it is very off that she didn't mention them to you as well. I don't know how much she wants to be in this relationship and you deserve someone who is honest and open with you. You need to take control and find out if this relationship can go any further. If not, you need to get out and move on. Wishing you the best.
