In the US, there have been quite a few cases already where teenagers have been charged with child pornography for "sexting", the practice of sending nude pictures of themselves to other teens using their camera phones. While chances are good that if such a conviction ever reached SCOTUS on appeal, it would be overturned based on privacy and freedom of expression issues, for now it remains illegal and there are people being prosecuted for it.

http://www.telegraph.co.uk/news/worldnews/northamerica/usa/4558848/American-teenagers-facing-charges-over-texting-nude-images.html