If I was a woman doing online dating and some random dude who I thought was cool sent me an unsolicited dick pick, what I would do is send back a picture of another random dick and make him worry that he'd been talking to a guy pretending to be a girl.

Then, after a couple minutes I'd just be like "now you fucking know how it feels to get a dick picture from someone you really don't want a dick pic from!"

If enough women did this we could eliminate the surprise dick pic problem in a matter of weeks.