He wants to keep pics of old girlfriends??

EDIT: Ok ladies i appreciate your feedback so far and I've pretty much dropped it. Until... I came across the stupid "keep" box, and the smaller box (made of wood, a very nice box... not something that he'd throw out) is MISSING!! I think he hid it... 😒 My boyfriend of 4 years and I are moving into our dream home. We were purging things we didn't need this morning and he came across a box of old photos of girlfriends--probably 5 or 6. I asked to see them and he hesitated but did show me. They're fully clothed and not inappropriate. He flipped through them quickly and and put them back in the box. I casually asked why he wasn't tossing them along with all the other stuff he'd thrown away, and he said "They're just photos from college" and put them in the "keep" pile. I mentioned that I didn't have any old photos of exes (even my ex husband who I was married to for 10 years) and he didn't say anything. Should I bring it up again or just drop It? I know he doesn't look at them or anything but why does he keep them?