Guys have been sending D-Pics since the technology was there to do it. In fact, we have talked on the air about how some guys jump the gun and send one waaaaaayyyyyy too soon.
Say for example, some guy you knew in high school finds you on Facebook.
Him: Hey, how's it going? Saw your profile and thought I'd friend you! How are you?
You: Really good! Glad to hear from you!
Him: You married?
You: I'm divorced and have two kids.
Him: (SENDS DICK PIC)
The female version is getting more popular. Probably not sent as aggressively and unexpectedly as some D-Pics, but the "slot shot" (thank you) is more mainstream than ever.
Here's an article from the New York Times.