The art of photography or art of anything, originates from the creators, yes ? Art in itself is an expression, a realisation of one's imagination. A sculpture, a movie, a poem, a painting, a song, a dance, an image, they are all a manifested output, originating from the artist's mind.
IMO that's the first half of what Art is, the second part involves us the audience.
But how do we separate art from some randomness ? We make noises all the time, we make photos, we write gibberish here. Surely they can't all be considered as Art of any kind. So is it fair to assume Art requires a certain degree of beauty ? that it is capable of projecting humanity's inner self ?
I believe Art is a reflection of us, for the better word, humanity. But sadly we are often too numb even to realise what is in front of us, let alone see its inner quality. We are quick to judge, quicker to reject, even deny, and spend too much time substantiating it (whatever it is).
If this goes any further, I'll be heading into the realm of philosophy, even spiritual, and end up writing "What is yoga". So let's default ourselves with the actuals.
In the state of our social hierarchy, art is quite literally, what the experts say it is and isn't. It matters not whether we like it or not. Recognition from the higher up determines what is Art, and it is reflected by the price tag. The higher the recognition, the more Art it is, and also the mucho price.
Leica Oskar Bernack Award is art, while Shutter Alliance award (if any) is a complete and utter joke.
The question now is, what is a higher authority ? To cut the answer short, an authority is an individual or a group of people, whom we all recognized, acknowledged and maybe admired. We trust them to tell us what is, gives us a structural direction, a goal to become a member of this exclusive fraternity.
Art is a complex subject, it will take years of study just to attain the minimal level of appreciation. Yet, art is art by merely "in the eyes of the beholder". To put it crudely, "It is, what I say it is".
And why not ?