I've written a reply....i can't see it now, so i'm going to re write it...
anyway...
I was reading this book of essays from Jerrold Levinson titled "Contemplating Art : Essays in Aesthetics" and there was an essay on Erotic Art and Pornography. I was researching into the work of R. Mapplethorpe, so it seemed appropriate.
Anyway...he poses the thesis that pornography and (erotic) art, cannot be identified as the same thing in any case because their intentions are contradictory. He contemplates that pornography aims at the sexual gratification of the viewer and usually negates, or even discourages the artistic interest of the viewer, whereas erotic art demands the viewers artistic interest, in relation to the form, expression and context of the picture.
He continues by saying that just as a painting can be photographic (style-wise) - and yet not a photograph, the same can be applied to erotic art. It can be pornographic, and sometimes even more explicit than pornography (e.g Mapplethorpe) but still be considered art, since it engages the viewer into considering the picture in relation to broader issues.
What i've found to be helpful in his essay is also the distinction he makes between Erotica, Erotic Art and Pornography. Erotica refers to the imagery which in context is similar to pornography (doesn't demand artistic attention - but isn't necessarily sexually explicit) . He gives as an example the "Victoria's Secret" imagery.
Anyway, it seems as if i'm summarizing the essay now... !
it's a good book...helped me for my dissertation :)