<human>: My roommate, whom is a very close friend, recently revealed that her boyfriend's friend showed him a naked pic of his girlfriend to him (and subsequently to my roommate). I'm positive that the girl has no idea that her pic is being shown to at least a few people. This guy isn't a great guy in the first place. He's stolen cash from people and done a few things that aren't exactly morally right. She knew this about going into the relationship.

I really want to tell this girl that her picture is getting around, but my roommate is furious that I would even think of telling her. She wasn't supposed to tell me that she saw the pic. According to my roommate, only three people are supposed to have seen the pic... obviously more have than that. 

This girl isn't a very close friend, but I feel obligated to say something. I know my roommate would be furious if I said anything because it has the potential of getting back to her and her boyfriend. 
How do I approach this situation?

Can you give me a shortened version of the text?
<bot>: Roommate tells me that acquaintance's naked picture was shown to more than one person. Girl probably has no idea. Should I say something and risk friendship with roommate?