I think porn is in the eye of the beholder. If it turns someone on then it's porn to them, whether there's nudity or not. And if someone else sees an image as art and isn't turned on, then it's not porn to them, whether there's nudity or not.
There is however one exception to the rule: If it was Miranda Kerr it was porn
I don't doubt there are people out there that think a fully dressed woman exposing arms, legs and a little cleavage is porn too.
However, regardless of personal definition, you would have to assume that if an image is not one that has been censored (and I don't believe this would qualify) it would not be porn in the eyes of the law (our defining benchmark ).