Though really, Ethan does have a point.

If an artist truly didn't want people to EVER take their pictures, simply not posting them would suffice. They could privately message people them, thus avoiding putting them in their profile. Set everything to private so that only people given specific links could view it, or Email the person the artwork. By posting them, every artist has to silently accept that someone, somewhere, will download it.

That's simply how the internet is. It's not a nice thing to think, but we would be in a utopia if it were not.

The downside is that people wouldn't be gifting them fan art of their characters that they like. But that would be a small price to pay for not having your artwork used elsewhere, right?