If we go by the idea that every school of art is an actual... school, that is to teach something specific, instead of a genre definition that excludes everything else, then the regular training in the core tradition is to help you improve even in your divergence, rather than tell you not to.

*bump*

In a transitioning interlope to topic, let's talk about this greatness of art.

Is art shallow when it doesn't claim "something deep", is art pretentious when it does?
Is something deep only if it is melancholic, mysterious, sad and tragic?
Great only if you are compelled to stare at it for hours, great for all people?
Great only if it has lasting mark historically on culture, maybe a great message?
Must you have put a lifetime of effort into a work to have it be any great?

I like Albrecht Dürer, but if every work of art were to become like his, because it is so great an art, it would have a harder and harder time affecting me, no matter how great it is technically and symbolically, its greatness cannot be greater than my moment of mood. The human soul is varied, and so is the greatness of art, and every element of this variety is deeply heartfelt, even the most cheesy romantic giggly huffpuff, even aggression, even hyperventilating rush, cruelty and mockery, or maybe tranquillity, maybe elegance, cliché beauty, or arrogance in technical superiority, and everything else... it's all part of how it feels to be, it's all truly deep, and it stops being deep without all the variety, that's when it becomes shallow and pretentious.

But you can look at this and say, this is the cutest thing I've ever seen, omg look, so cute! and marvel giggling stupid at it for hours, and for you that's a deep experience, as is for the one creating it, while everybody else deems you two shallow, maybe because they are too sad to feel the depth of simple happiness, and vice versa. Or you are mesmerized by a detail of the work, a specialist accomplishment, maybe even something about the process of work, and the big picture doesn't matter for you, maybe not even the result (some even say any result itself of art at work is worthless, and audience can only be shallow), at this moment all you care about is this little something that captured your curiosity, whatever it is, it is so peculiar, it's great, this little thing is a deep world for you, and right now you couldn't care less about the deep greatness of those other big things that are great art, and no one else's opinion changes that, while at the same time you become super shallow for super-imposing its greatness on everything else, to everything's disgrace.

Maybe rather than "great art", we should say "This artwork is great at ... when you are looking for ...". It doesn't need to be super popular to be great, it just needs to be great at something to someone, not at everything it wasn't meant to be, to everyone who cannot see. Popularity is a quality in itself, yet it doesn't measure every other quality of it in greatness nor graveness.

You know Kant's "the critique of pure reason"?, we're talking the artistic limit of pure critique here.
And beyond either limit is the true greatness, and the only way to get there is humility -- a great critique roots in appreciative humility and curiosity in a benefit of doubt.
So that the notion of "great art" doesn't devolve into a question of "real art" -- maybe an oxymoron.

@Hapiel
We'll come back to it when it's time hap, no worry, but this here is interesting enough to warrant a little detour.

@Helm
You see, that painting did for me as well, I absolutely am a fan of that kind of almost mythological or super-sense-ical stuff, it probably is my personal preference as well. But I also can very much enjoy a broad spectrum of art altogether, each for its own merits. I have you know that I am indeed playing devil's advocate here as you assume, it's not that I have my own creative stake in it, but this touches a lot of philosophical interest I am curious about indeed, and I believe this needs in-depth debate as has happened. I like this place here.

What evokes emotion is in the eye of the beholder I believe. It probably is problematic to make the title of art depend on one persons impression of emotion. Maybe it's better to search for the creator's intend, and many of them, cheap and utilitarian they may be in the aspects you care most about, have other aspects you can clearly see an artistic aspiration, that work on someone open for it.

For example, on that fighting choreography fan-art video, you can clearly sense the animator's experience with dancing, which by itself is a form of emotionally expressive art, as is martial arts in its forms and traditions. In many moments of that video you can sense beautiful elegance and emotional impact. Aspired movement as an emotive language, and thus animation, is art, as is arrangement of scenes, and dramaturgical direction, even if the assets themselves are doubted in their artistic origin, the result contains artistic effort enough to be art. The paper and pencil, as tools and you may even call them assets, are not art, but the drawing is, and that the result also contains "doubtful" elements beyond as a means to an artistic end, you may call these assets also tools as much, still makes it art in the end.

Maybe our disconnect comes from discussing copying in different context unaware? I speak of copying in a value-free manner, you seem to mean copying as in ripping other people's work off uncredited and for personal profit -- I am against that. As much as I am for fair use.

However, in that sense, when looking at photography strictly, does every photo show only assets owned by the photographer? Are photos showing objects not in your possession ripping someone else off? Or is it the arrangement itself that makes you own your photo, and an obvious effort in arrangement of photo-sources that makes you own the mashup?

Obvious effort in arrangement makes the difference. Just copy pasting someone else's carefully arranged photo art, and that's fuck all, is rats, we agree altogether wholeheartedly. But if the new work is so intensely involved that small samples of various sources become an almost unrecognizeable and minor footnote each on its own, I don't think that's rats, or kinda everything is rats on merest inspiration in any form of art. Frankly, as much as photographers "do not simply flatten reality", photo-sourcers, as demonstrated some day earlier, do not simply "copy&paste", there is definitely much skill involved. There is obvious care in creating the illusion of light, ambiance and composition, and real photography is not any better than the chopping and arranging of objects real life as well. All that talk of differences is romantically super-inflated, to be honest.

Examples have been already given, but it seems to me that the focus in critique has been too lopsided, and I don't expect that to improve. You may have missed my edit in the earlier post fielding points about photography itself as art as much as literal copy technique, the *arrangement* is the relation to subject. If you've ever been impressed by photography, you've been impressed by copying. And if not, your definition of art seems narrow to me. I don't think that's a copout.