Is it rude to turn art into porn? To take a shot originally intended as art and present it in a sexual context? To change the artists intentions? Assuming we can judge their intentions of course.
The most obvious cases of this are image captioning – literally putting words into peoples mouths. A good number of these take regular non-pornographic imagery and re-cast them into a pornographic context. However, even posting an image to a themed tumblr or a blog like this changes the interpretation. I sometimes wonder about the rights and wrongs of that.
This image is of Anna Monroy di Giampilieri, shot by Slim Aarons in 1984. He was an American photographer, famous for his images of celebrities and what in those days was known as the jet set. It clearly was intended to capture the wealth, power and beauty of his subject. I think that also makes it work for the Femdom inclined, but wonder how the artist and subject would feel about that.