Pornography= art?

There is much speculation as to whether the works of Edweard Muybridge are closer to works of scientific experiment or works of art. In addition, there are people who speculate that Muybridge's works were forms of art and, in addition, pornographic forms of art.

It seems that there is a fine line between what is pornography and what is not. While to many people in today's world Muybridge's work seems relatively mild, to the people of this time it might have appeared to be overly promiscuous (i.e. the images of women pouring water on each other or rubbing each other). The question of whether his work is pornography almost seems to pertain more to the time period being applied rather than the actual make-up of Muybridge's work, for people today will certainly have different takes on his work than people of the time the works were created.

Did Muybridge simply have "scientific" reasons for using nudes and semi-nudes in his work? Why was this, if his work is indeed scientific, scientifically necessary? When considering Muybridge's odd life outside of his work with locomotion-changing his name, almost getting killed by a stagecoach, killing the man who had an affair with his wife at point -blank range-it is questionable as to whether Muybridge had a direct purpose in using these naked and nearly-naked figures or if he was just a little bit on the loony side. So the basic question is, was Muybridge's work scientific or artistic, and furthermore was it a form of pornographic art?