i just remember this movie, good morning mrs henderson by judi dench?
and there, she was opening a performance show with nude girls. and the law was stated that as long as the "object" didn't move. then it's not considered phornography so she asked the girls to poses like a statue or a painting to be not considered as phornography :)

I suppose there's lots of ways to perceive and interpret images. Whilst taking the image as a representation, is the image selling an idea, or is the image purely presenting itself with the subject content of the image. Pornography or not pornography or fashion photography would be just a matter of how the subject content is being presented in the image.

Here I would end off with a quote by Richard Avedon,
"All photographs are accurate. None of them is the truth."