It’s called “sexting” and it’s when a naked or sexually suggestive photo, video or message is sent with a cell phone. In many states it is treated the same as child pornography, and is considered a federal offense to have child pornography in your possession. A teen can be labeled a sex offender and be treated as a criminal for sexting.
Once a photo or message is sent, there is no guarantee it won’t end up online somewhere, where you won’t have any control over who sees or uses it.
It takes just a few seconds to send a photo, but it would have a life long impact.