As I see it, within a couple years this tech will be so widespread and ubiquitous that you can fully expect your asshole friends to grab a dozen photos of you from Facebook and then make a hyperrealistic pornographic image of you with a gorilla[0]. Pandora's box is open, and you cannot put the technology back once it's out there.
You can't simply pass laws against it because every country has its own laws and people in other places will just do whatever it is you can't do here.
And it's only going to get better/worse. Video will follow soon enough, as the tech improves. Politics will be influenced. You can't trust anything you see anymore (if you even could before, since Photoshop became readily available).
Why bother asking people not to? I guess if it helps you sleep at night that you tried, I guess?
[0]A gorilla if you're lucky, to be honest.