Well, I guess it really depends. By definition, art can be one's every kind of expression. But what makes something pops out as art for most of society is it need to be circulating through the art world "web", like museuns for instance. The moment you are inside that web, being promoted by a curator or something like that, even Duchamp's Urinal can be called art.
But, there's also commom sense , cultural sense and personal taste (?). If you think that the image you posted is art for you, then art it is. :P
It is also very related to people. If someone is already inside that "art world web", by definition, an "artist", the person's name is already linked to his/her work, therefore automatically giving it the title of "art".
Of course most of what I said is more related to contemporary art, because classical art have some distinctions.
I may someday make a post talking about that, if you are really interested, you can follow me. xP
You are right. Thanks. :)