For minors...
Not if you send them. Who ever is in possession of them can though and you can't (legally) get in trouble for having pictures of yourself. But your legal minor status depends on where you live.
The blackmail thing isn't much of a worry, unless maybe you want to run for office. I used to strip and I'm sure people have taken pictures of me at one point or another. If it ever comes up just don't let it bother you. Your body is nothing to be ashamed, ever.