Yes, frequently.

Once a friends girlfriend was going to show me a picture of something on her phone and a picture popped up of her getting slammed by my friend she said uh oh and quickly got rid of the pic and turned her phone away so I couldn't see. I didn't say anything about it so she was only slightly embarrassed.

A female friend showed me a video of her having colonic irrigation,legs open,pussy in all its glory,she told me her partner fucked her arse when she went home afterwards and showed me a picture of his cum on her pussy and a gaping bum hole.I was quiet lost for words!

I am on a bowling team with my wife, my daughter-in-law and another friend who is female. The friend was looking for a photo of something on her tablet to show us when a photo of her husband nude and erect popped up. She acted embarassed but left it there a few extra seconds and then moved on. Later when both my wife and DIL were away from the table she showed me a nude of her saying it was only fair. I then showed her one of my erect cock, since that was only fair too, lol. We both thought a lot of each other but nothing else has ever came of it.

I have a lot of nude pictures of female friends, I don't post them because I haven't gotten permission or asked them if I can post them.

No big deal. Current generation isn't hung up on nudity like our generation is. I have seen a few nude pics of friends of both genders (and I know that genders aren't binary)

Because after I asked her she said "sure I don't mind, I love being nude. It's perfectly natural".

Sounds like you catching a glimpse of your stepdaughter's friend was purely unintentional and accidental.

I'm curious, why didn't you just let it go rather than ask her if you could further view her personal picture? Surely you made an unfortunate situation even more uncomfortable.