Boyfriend is mad I wouldn't send him naked pics; am I in the wrong?

No, your boyfriend is being completely insensitive and irrational of your feelings. You should probably call him and tell him that you're sorry, but you will not compromise your morals, and that if he really loves you, he won't make you do something you're uncomfortable doing. By sorry, I mean a more sarcastic harsh sorry, not a true apology. Hopefully, he will be the man here and accept your feelings. It seems he gets easily upset over little things. I don't know what type of relationship you have with your bf, but if it were my boyfriend, i would've said, "I will, so long as you send me a pic of yours too.", making it clear in a subtle way that I expect equality in the relationship.