Found a racy image online that looks like my friend, what do I do?

A nude website (it claims to be artistic) I’ve been browsing happened to have a photo that looks way too much like a friend of mine (..and way more than I’ve ever seen (!) Do I tell this friend about it? Also, if there is no contact info on the website, how would this friend ask that the image be removed if it was without their knowledge or consent?