riotgirl and Perna made some excellent points. Your ex BF is counting on you being scared to get you to come back to him. He's not only a blackmailer but he's a psychological abuser. Him doing this is much worse than a few nude pics. If my daughter came to me with this, I would support her completely. He's looking for you to be scared. Anyone seeing a nude pic of you is small compared to you giving in to him.

You should tell the school officials and I promise they've heard this before. Don't show fear and even if your pic go across the world, you don't need to feel shame. Its only a body and we don't even judge you. I guarantee he'll be scared if you go to the police and make the school aware. People with schizo - affective disorder are fearful of authority. One more nude body on the Internet is no big deal overall, so don't think its devastating. Be stronger than he is and never go back to him. You're not alone.