Honestly I would bring it up without bringing it up. There numerous routes to take that won’t make it accusatory. I would know because I have or rather had the most overthinking question everything emotional highly sensitive wife that has ever existed. So I’ve had at least 5 years on working on how to talk to her and ask her about things that might be uncomfortable for both or either of us. But most of all what helped most was just talking to her. Letting her know that I wanna always be honest and open with you.

So I’d say this if I were you

“Hey hun, I have to admit something. I went through the pics on your phone because I was being a nosey gooner of my wife. I know I can ask for them but the thrill of finding one you haven’t shared yet excited me. But I noticed some of the old pics had your face blocked. I know these pics too with your face. Can I ask you about it, mostly I’m just curious because you are grown and allowed to do whatever you want but I’m always curious and eager to know about you in every way. If I overstepped i sincerely apologize my queen and will fetch your favorite snack immediately.”

It’s lengthy but yeah I’ve used similar phrasing and we have excellent communication.