Porno? No. There can be nudes that are considered art, but I would compare porn to more of a product than an art. There's no easy answer to this, and there's going to be a lot of different views.
Here's how I'd compare it: go to Target and look in the kitchen section. There's some coffee makers or mixers of microwaves that are beautifully designed, but I don't consider them art. Although yes, there is a certain element of artistry in items like this, in the mundane. But when I buy a toaster, I'm going to use it for toasting bread, not hanging up on my wall.
Porn is like that. I don't want to be crude, but when looking at porn, I'm looking at it for a specific purpose. Yes, there may be an element of artistry in this angle or that one, or this shot follows the rule of thirds or is well lit, but I don't just watch porn and admire what the cinematographer did.