There are a number of reasons to think twice (or three times, or four times, or fifty times) before sending a nude photo of yourself to someone electronically. But, if you're under the age of 18, there's at least one big, glaring, serious reason: you and the recipient could be charged with trafficking child pornography. If you think this sounds crazy, it is exactly what happened in Greensburg, Pennsylvania after two teenage girls send nude photos to some teenage boys.

Two girls from Greensburg, who police say are "14 or 15" years old, allegedly sent nude photos to two boys who are slightly older than them (16 or 17) using their cell phones. The photos were discovered in October after one of the youngsters was caught using a cell phone during school hours—a violation of school rules—and had the phone taken away. The photos were discovered at that time—I didn't know teachers could go snooping through your cell phone, either—and turned over to police.

"It was a self portrait taken of a juvenile female taking pictures of her body, nude," Greensburg Police Department captain George Seranko told WPXI News. "Taking nude pictures of yourself, nothing good can come out of it."

This might seem like a one-off story, but last month, the National Campaign to Prevent Teen and Unplanned Pregnancy released survey results that said 20 percent of all teens have sent a nude photo of themselves to someone else electronically. More than two thirds of those who have sent photos claim they sent them to a boyfriend or girlfriend, but 15 percent say they have sent them to people they only "know" from the Internet. And they're not staying private, either—a quarter of teen girls and a third of teen boys said that they've had nude images originally meant for someone else shared with them.

Though the discovery was made several months ago, the Greensburg Police Department apparently decided to arrest and charge the teenagers this week. According to the police, the two girls are being charged with manufacturing, disseminating, or possessing child pornography, while the two boys are being charged with possession of child porn.

We'll have to wait and see whether anything actually comes of this case—like cases involving underage sex and statutory rape, there's a huge and inconsistent gray area when it comes to teens dealing with other teens. One thing's for sure, though; the students at the kids' high school will probably be scared straight about sending nude photos to each other—at least until the end of the school year.