Is it wrong to masturbate to someone I know from high school's pictures on insta?

There's this girl that I used to go to high school with (both 21 now) and she's been posting a few revealing photos on her instagram and I can't lie, it's turning me on a bit. We didn't really speak often but when we did it was 50/50 in terms of good/bad conversations. She's super left leaning and I found some of her opinions on things to be super radical at times and it was also funny arguing with her. She was also one of my closest friends gfs at the time so I think that's why we made up everytime we argued. After high school it was mutual between us and like a year later her and my friend broke up. Their relationship in high school was pretty cooked, they were that couple that would break up every couple of weeks then get back together.

So, that's the backstory. Has anyone else been in this situation? I just feel bad because 1)She's my friends ex and I'm not sure how he'd be if he ever found out (he never speaks about her anymore) and 2) is it morally wrong?