Check out this link. It's an interview with Witkin. Quite the sick puppy in my estimation. But then again there have been quite a few quite mad creators of exquisite art thru time. I don't feel he was trying to be shocking, but rather was trying to satisfy his own cravings. The use of a camera and the "respectability" it brought just gave him easier access to the dead and decaying he seemed to need to be around and fondle in his own way.
As far as his art is concerned, it's not for me. But that doesn't make it art in some peoples eyes. I would classify this type of image making as satisfying some sort of fetish. Many of the Betty Page pictures were created to satisfy various fetish needs of the publishers customers. Some of those images are now considered "art". Those that truly appreciate them as art probably don't derive the same sexual kick that the original intended audience did.
So this begs the question, how does something transform itself from fetish/shock/schlock imagery to art? Is it because we are now able to appreciate it on a higher level? Are we now seeing past the originators demons and into their souls. Are we now recognizing the contribution of that part of the creators persona that is/was connected to a higher plan?
Or is it because we have become so jaded we are no longer moved by the original message and reduce everything to lines, tonality, focus and S curves?