@ehBeth,
ThT was my first thought ehBeth. Seems that, except for punkey, we're all on the same page.
The only thing I would add to the OP is to really ask yourself if you weren't snooping just a little bit.
I can't imagine how they weren't in some kind of box, envelope, electronic storage device or at least enclosed in something.
Did you have to in any way open something to find these pictures?
Or were they just scattered all over, face up, so that you had no other choice to see them when you went into the closet?
Maybe you're uncomfortable with asking him about it because he would be within his rights to ask you why you were looking through his things.
If you were, why were you?
If you were, you need to keep your mouth shut and move on. They won't be fresh in your mind forever. If they are, you've got other issues you need to work on.