Tell a friend I saw her nude .gif online

I saw an online nude .gif of a young woman I know. It's not porn, per se, but it is full frontal. It looks like it may have been private between her and her man. It's been reblogged hundreds of times. Should I tell her? I don't want to embarrass her, and I don't want to ruin her vibe by setting up the impossible (published on the internet = cannot be erased). And I don't know if it was posted with consent. I don't want to interfere, but sort of feel like I should let her know at least. She's recognizable, obviously.

I don't know HIM. I have no idea who HE is. I only know HER. And if he is the one who posted it originally, he already knows it.