in which rarity teaches applejack about art
It was a bright sunny day in Equestria (but you don't really care how the weather was do you) in a museum in canterlot. A crowd of ponies had gathered for the opening of a brand new art gallery in honor of the princesses. Paid for by prince blueblood himself (go figure)
In front of the crowd of the upper crust, unicorns were two of the elements themselves. Rarity, the element of generosity, being a fashionista and famous designer all over Equestria, was naturally a purveyor of the fine arts, and enjoyed staring at these models. It truly is fascinating how one canvas could hold so much beauty.
Also, there was the element of honesty, applejack.
Applejack was there for the free food.
The two ponies stood behind the ribbon, soon to be cut by the comically oversized scissors. Prince blueblood looking smug about his collection, applejack looking bored out of her head, but respectful of where she was. (learning from "honest apple").
"It gives me great pleasure to ask two of the elements of harmony to open the prince blueblood exhibition of very expensive paintings he couldn't find room for in any of his houses" was the announcement given by the owner of the museum as he welcomed the two ponies to his side. The two greeted with the light clapping of hooves
Applejack stood by rarity, still a little confused as to her presence "ah declare this..... Open." with that, rarity used her magic to lift the scissors and cut the ribbon in two. The pair of element bearers were the first to walk into the new gallery. The first thing they came upon was two paintings side by side. The smaller one was a detailed picture of the powerful stand they along with their friends took against the group entitled "the legion of doom" in a battle for Equestria itself, a proud achievement indeed 
Next to it, a much larger painting simply depicting twilights cutie mark, very simple, too simple
Applejack looked at the bigger painting thinking to herself "is this art?" after a bit, a silent Applejack spoke up
"See, this ah don't understand"
Rarity looked away from the painting and towards applejack "what do you mean darling"
"Ah I ah don't understand how a painting as simple as that could need this much canvas, y' could fit six of this beautiful painting in that overblown thing"
Rarity looked at the larger painting cock-eyed "well, I suppose that is true" she agreed in a sense.
"Speakin of which" applejack continued, "how much did them two paintings costs" rarity responded "well, I'm told this one worth half a million bits and that one's worth three-quarters of a million"
Applejack, puzzled that such a simple dull artwork could be worth more than that masterpiece, asked "now, how come that ones worth more than that one" rarity simply condescended "oh, applejack, can't you see the difference"
The earth pony looked again for a moment and saw no difference apart from the one that was already addressed, she nodded no
"That one is much bigger"
"So the photocopied cutie mark is worth more in gold than a painting what looks better than real life" applejack queried. "
"I suppose so," rarity said. They looked away from the art and began walking, their hooves stamping down on the polished floor. Applejack asked again "so is that t main consideration fer art?" "it's the only consideration darling" rarity answered
She then continued "it's about SIZE. The bigger it is, the more money it's worth. I mean you can't expect to get a family estate for the price of a beat-up wagon wheel, can you now"
"Ah suppose not, but that's a ludicrous way to price a work of art, suppose if I made a masterpiece on a grain of rice, meanwhile some untalented bozo threw some paint on a wall and called it a day if we both put our artwork up, I'm walkin away a poor man's pony"
"Well, that's the way things are run in this world" rarity replied, "the bigger, the better" as they continued walking through the halls of varying quality in artwork, from beautiful statues to multicolored cubes, to a strange one of celestia's face posted a 1000 times on a sheet. Applejack and rarity came to one of a group of their friends in 1800s prance entitled "Sunday afternoon in a park in ponyville
her first thought was why was she lying on a towel seductively, that part freaked her out slightly. but then She began to look intently at sweetie belle, her focus becoming narrower and narrowing as focused on the face, normally, applejack wasn't much for detail as she focused on the practical, but here, she could really appreciate just how detailed and realistic the photo was, almost like they were trapping ponies in there, she smirked as such a crazy idea. Particularly, she was impressed at how the artist went as far as to get the eyes correct with their retinas and pupils. She found herself staring directly into sweetie belle's eye for what seemed like an eternity. She had looked so hard she could actually see the microscopic dots on the canvas, millions of little dots making up the big picture.
She finally snapped out of her silent wonder. She turned to rarity to resume their conversation about the art, she brought up another painting of great significance to the art world and the only one she had known up to today.
"Y' know the Mona Lisa is not that big, is it, and that's supposed t be the most expensive one in equestria"
Rarity, knowing exactly what applejack was talking about, corrected her "ah, it's deceptive you see, it's very thick"
Applejack raised an eyebrow at this strange development about the priceless painting.
"Yes, you see the artist often used great big dollops of paint in his work, so in fact, it doesn't work particularly big, but it's a very very deep painting."
"Kinda like this one" applejack remarked
"Yes exactly" rarity confirmed. "Size and bigness are all that counts in this industry, they couldn't give a toss about the art in question"
"Well, I'm gettin that impression certainly"
"Oh, that's another bunch
"What the certaintlies?"
Rarity giggled at her friend's naive answer "no, the impressionists" she explained
"Now to the untrained eye, a lot of their paintings are very small, but they are in fact, very big, they just give the impression that they're small, hence the name"
"The smalls?"
Rarity chuckled again at the naive question, and corrected "no no no no no, the impressionists"
Applejack also shared a small laugh at her question, confused about what the art ponies valued, but appreciative of what was on the canvas.
"Say, what's that one suppose t be" pointing to a realistic painting of twilight whose main feature was the eyes again. 
Rarity was happy to point out "ah, now this is from the realist school, some say it's so lifelike, that it actually follows you around the room"
"Boy, id hate t see that in the middle of the night"
The two ponies shared a hearty laugh over their shared discomfort of the realist painting.
It had been an interesting day, as even something as simple as focusing our eyes on smaller things we see proves just how important everything is to its world. As the two continued to walk past the many paintings, the eyes of twilight as discussed were following the many attendees around the room, any way you looked at it.
Prince blueblood looked directly at the painting in curiosity, and could swear that the lavender unicorn was winking at him, he shuddered a little before moving to the next painting.