The difference between exhibitionism and swinging is the difference between looking and touching. I might enjoy having sex in front of a crowd, but it doesn't mean I'm willing to have sex with any or everyone in that crowd (whether or not I might fantasize about it in the safety of my own head). My erotic photography is not an advertisement for a product that can be bought for the right price. My erotic photography is the product. Some people would argue that it's a tease, that there's no value in arousing one's sexual desire unless you also intend to satisfy it. I vehemently disagree. I think there is intrinsic value in the eroticism itself, apart from any consideration for sexual satisfaction, and I also think satisfying oneself to an external stimulus is a perfectly respectable alternative to having a stimulus that actively satisfies you.
It's not unlike the argument that girls who dress provocatively and don't put out are asking to be raped. My sexual attraction to another person is not their responsibility, and if I find someone attractive, they have no obligation to me. I could be attracted to someone who doesn't dress particularly provocatively, or I might be drawn to an element of her clothing or style that she hadn't intended or expected to be attractive. This does not imbue her with any sort of responsibility to my sexual desires. And it's no different if she wears something that our culture defines as provocative, and expects to be accompanied by promiscuous sexuality. Regardless of a person's intentions with the way they dress (or act, or simply look), the only and responsible way to know if a person is interested in a certain type of activity is to ask her, not assume, based on appearances.
I welcome the internet because it greatly facilitates the practice of voyeurism. But we need to divest ourselves of this belief - particularly rampant concerning the interpretation of pornography - that a sexy picture is intrinsically related to sexual activity. If the picture depicts sexual activity, then it is obviously related to the sexual activity that it depicts. But if it does not, then we cannot presume that a certain body posture, or a come-hither stare, or the style or lack of clothing, or anything, is an invitation to sexual activity, when it could simply be flirtatious and sexy (not sexual) behavior.
In either case, there can be no presumption of a link to any other sexual activity that follows the display or sharing of that picture (and we must differentiate between independent sexual behavior, and sexual behavior that actively involves the stimulating subject - in other words, jerking it to a picture on the web is not equivalent to having sex with, much less raping, the person in that picture; all the more so if that person has absolutely no idea). Again, it all comes down to asking what a person wants. Pictures are not a "fuck me" permission slip (in your dreams), any more than wearing a miniskirt or flirting are. And neither should we treat them as if they were such an invitation to loose and licentious behavior by censoring them. A picture is just a picture, depicting only what it depicts. Nothing more. Anything else that might come of it is courtesy of the installment plan, and can be billed exclusively to those active participants who are responsible for it.
Hang on, "fuck me" permission slip? ...Oh, I just had a wonderfully naughty idea. >;-)