I wonder why he is doing the photo shop on his female friends. To me, it means he has more than just friend feelings for them and wants to imagine them naked.

You seem to be comfortable with his doing this, as far as how it pertains to your relationship with him. Also, you say these women aren’t your friends and don’t like you.

So, I have a take on this that might be unpopular with others here but— I’d say don’t tell them. They don’t have knowledge he is doing it. He is not harming them by releasing the photos and slandering them. You know him well enough to know he is not a physical threat to them. He’s not having sex IRL with them or attacking them, I hope. So, what they don’t know doesn’t hurt them. It’s not your responsibility to tell them.

Personally, I’d have real issues with my bf doing this to me. It’s like he’s cheating on you. He has relationships with other women who he fantasizes about naked and he knows you know. But, you seem okay with it, so no judgment here.

If he was a real threat to them, then I’d warn them. Otherwise, you are just causing tension between them, him, and you.