is that all he has done? who is this girl? what made him do something like that?

If you care about him, you can still be a friend. Ask him to tell you WHY he sent a pic of (himself) to another girl. You already know he's suicidal, so talking to him about this makes sense. Maybe he resents the fact he screwed up and he does want to be with you. People make mistakes, a friend would forgive and listen to what he has to say. You still care about him deeply, but are hurt from what he's done. Tell him you are still his friend, and if there is a possibility you can get back together......then it will take some healing time.