Definitely not art.
It seems a lot of people are concerned about which pics of naked women they are allowed to post.
They wish to preserve their lefty Tumblr street cred but they also really, really like naked women. Nearly as much as kittens falling over backwards and Frozen.
Here’s your answer:
If the woman looks really unhappy about being naked, is holding a spoon, icosahedron or doll smeared in menstrual blood: THAT’S ART. Post it and if anyone calls you out, sneer at their lack of art appreciation or, if pressed, claim it’s ironic. PLUS POINTS if the woman seems totally unaware she’s taking part in a nude picture, DOUBLE PLUS POINTS if she’s texting at a bus stop or near some knives.
If the woman looks happy and confident in her naked sexuality: THAT’S PORN. You MUST NOT POST IT or you will lose cred. You MAY POST if the woman has full sleeves, a liferuiner or similar coolness. EXTREME MINUS POINTS if the woman is actually smiling.
There you go, Tumblr. Now all you gynephiles can breathe more easily and store up pics for your wank banks with assured impunity.