Did you ever stop to think that maybe you're dealing with stolen art?
Probably not, but your jaw might have dropped at the suggestion - what if that awesome photo or digital painting or vector you just faved WAS stolen? Unfortunately, the Internet being what it is, there are very few ways to be completely sure any given image wasn't stolen. But here are a few tips to determining whether or not it was.
1. It's in a stupid gallery.
By a "stupid" gallery, I don't mean slightly off - photos that belong under Landscapes but ended up in Geology don't count. I'm talking about beautiful digital paintings in Fractal Art, or heartstopping candid photos in Anthro, or amazing photomanipulations in Body Art. Stuff that makes you go "what kind of idiot would put THIS in THAT gallery?" Creating a beautiful work of art, even with a camera, is not a point-click-shoot deal. It takes skill, dedication, and care. And someone with that much dedication, even if they barely speak English, is probably going to put forth the effort to make sure their beautiful work of art ends up in the correct gallery, or at least close to it. An art thief's care and dedication generally begins and ends at "will this earn me faves?" They're not nearly so concerned about what gallery their stolen art ends up in, as long as it's in their gallery and looks good.
In short: Awesome art + ridiculous gallery = probably stolen.
2. There's a watermark or website URL on it that doesn't seem to go with this deviant.
I know, this should be obvious - that is the whole purpose of watermarking, after all. But it's only obvious if you check for one; not all artists like messing up their image with a huge, obvious watermark and instead put a small one in some obscure place. If it was submitted by BobJones123 fifteen minutes ago and is signed "KLY 2005", or it has the address "yourarthere.com" and the artist doesn't mention owning, working for the company that owns, belonging to, being affiliated with, or submitting art to "yourarthere.com" (check their journal, just in case), it's probably stolen.
In short: Unrelated watermark/URL = probably stolen.
3. The image is very finely detailed, but the fullview or download is very small.
This mostly applies to digital art, especially digital paintings - with traditional art, the size of the scanned or photographed image may be very small compared to the original, and it would be no fault of the artist. However, digital artists don't have to scan or photograph their work in order to submit it, so they can submit it full-size. It's very, very difficult to create super-fine detail in a very small space, and most digital artists, no matter how skilled, prefer larger canvases. Besides, if they didn't like to show off, they probably wouldn't be submitting their art here; they usually want people to see and admire all their hard work in some larger format than the default, even if they don't offer the full-size image for viewing. If someone is submitting the original of a super-detailed work of digital art, that original is probably going to be at least of a decent size. And if someone is painting something of similar complexity to The Last Supper on a canvas the size of a 3x5" notecard, digitally or traditionally, odds are they're going to brag about it. If someone's submitted a beautiful, detailed digital painting the size of a postage stamp, and they're not saying anything along the lines of "Look what I did with such a tiny picture! Isn't that awesome? What a pain it was, but it was so worth it!", they're probably submitting a stolen thumbnail, or a shrunken form of a larger original (possibly shrunken to hide an annoying watermark).
This doesn't apply to pixel art, because pixel artists almost by definition work on very small scales with incredible detail, or to fractal art, because it's not only possible but easy to create a very detailed and very small fractal.
In short: Super-detailed + very small = probably stolen.
4. The deviant admits they found the art online, or in some other way indicates the image isn't original.
This is why it's always a good idea to read the artist's comments. They do this more often than you'd expect. This doesn't mean they're crediting the artists whose stock they used in a photomanip, unless they were dumb enough to directly rip off the stock. More typical is something along the lines of "i found this on photobucket and i liekd it". (Be careful you don't try to accuse clubs of art theft!)
In short: Deviant says it's not theirs = stolen.
5. There's a spatial mismatch.
This applies pretty much exclusively to photography. Say you find a beautiful picture of the Sydney Opera House submitted by 11marchboogle11. 11marchboogle11's profile states that he/she/it lives in Canada. It's a long way from Canada to Australia, so if 11marchboogle11 had made such a long trip, you'd expect to see some mention of it somewhere, whether in the Artist's Comments or in their journal. But as far as you can tell, 11marchboogle11 hasn't traveled even as far as the United States. How, then, could they have taken this magnificent photograph? The short answer is, they probably didn't. The photograph was probably taken either by an Australian or by someone who's been to Australia.
Note: Don't rely on this alone. It's entirely possible that they did mention the trip in a journal that's been buried, or in the Artist's Comments of a different photo. If they have a bunch of photos from Australia that were all taken about the same time (they should also all be from the same camera), they might very well have been on a trip and just didn't mention it in every single photo. (If the camera specifications and date taken don't show up, and it's obviously a photograph, that adds to the chance that it's stolen.)
In short: Photo taken somewhere the deviant hasn't been = probably stolen.
6: The deviant just submitted a boatload of gorgeous art. Bonus points if they've been on dA for a month or less.
This isn't necessarily a giveaway, unless combined with #1 (stupid gallery) or #7 (all over the place), and it doesn't work so well for photography. But if they're suddenly submitting a whole bunch of beautiful pictures within minutes of each other - the sort of pictures you just know took hours or days of effort for each one - either they've been creating art for months or years and are just now submitting their life's portfolio to dA (or are submitting a backlog, if they're not a new member), or they're submitting all their favorite pictures to dA heedless of whose pictures they are. And if they've been making art for a much longer time than they've been on dA, or are a long-time deviant catching up on a backlog, they'll probably mention it somewhere.
In short: Whole bunch of new images at once = possibly stolen. Whole bunch of new images from a new deviant = probably stolen.
7. Artistically, the deviant is all over the place.
They're submitting text art. Oekaki. 3D images. Traditional sketches. Digital paintings. Photomanipulations. Landscapes. Fetish portraits. Action shots. Their gallery covers so many styles and media it looks like a patchwork quilt. Now, you could be dealing with a true Renaissance artist, an extraordinary person who possesses great skill in multiple areas. You could be dealing with a dabbler, who's trying a bit of everything in an effort to find what sort of art is really "them". Or you could be dealing with an art thief. Renaissance artists are few and far between, and tend to win fame and acclaim for their abilities. Dabblers tend not to be all that good at anything, and if they are, it's probably just that one thing (unless they're a budding Renaissance artist, which is really unlikely). Art thieves download whatever looks good and submit it. Renaissance artists are very, very dedicated; they tend to take a great deal of care and time even with their scraps, and usually take a pretty long time between submissions. Dabblers aren't necessarily going to take as long, but since they're also doing their own art, they're not going to be churning it out at a blistering rate either - maybe a few a day. Art thieves might be submitting a picture a minute, if they're on a roll.
Now, it could possibly be that you just found a Renaissance artist who just joined and is submitting their entire portfolio, or one who's catching up a huge backlog. This is where #1 comes in - if all the art is beautiful or at least appealing, and it's all in the same gallery, it's probably all stolen.
In short: Art all over the place = probably stolen.
8. Even though it's all in the same category, it's stylistically all over the place.
Say you just found someone with a gallery full of beautiful digital paintings. On this one, they seem to have a really beautiful and unique way of painting fire. But this one also has fire, and it's not nearly as beautifully painted as the other one. This girl's hair is so gorgeously painted it looks like you could reach out and stroke it and it would feel silky under your hand. This girl - well, her hair is also beautiful, but it doesn't exactly look like you could stroke it and have it feel silky, and the way her eyes are drawn is totally different too. But the way the leaves of the trees behind her are painted - they're not very detailed, but their blurriness provides just the right touch of softness. But wait - in this picture, you can pick out every vein on every leaf on every tree, yet they're no closer to the front. Granted, artists do change their style sometimes, but usually not suddenly and drastically, not from picture to picture to picture, and often not without mentioning "Hey, I know this isn't my usual style, I'm trying something different". When you notice the style keeps changing, even if the medium doesn't, start checking for watermarks, and take note of how far apart the images were submitted.
In short: Style keeps changing = possibly stolen.
9. It looks like an in-game screenshot, or like it was taken directly from an anime/manga/cartoon/comic.
It probably was. There are artists on deviantArt who can make their original artwork look almost exactly like high-quality anime screenshots, or like professional comic pages. Ripped art is likely to be worse - grainy, smudged, showing visible signs of compression, etc. And shockingly, taking screencaps straight from a game or images directly from a TV show or comic, submitting them without doing a thing to them, and calling them your own art isn't allowed, unless you actually did the art for the game, TV show, or comic. See, the people in charge here like you to submit your own art. You know, stuff you actually put a little bit of thought and effort into.
In short: Looks like a screenshot = probably is.
10. The artist comments are so badly misspelled and grammatically messed-up as to be incomprehensible, or is just a bunch of meaningless gibberish - or worse yet, nothing but punctuation marks.
Creating art does require a certain amount of intelligence, and artists tend to like to brag. At the very least, they'll often identify what their deviation is a picture of, or maybe how long it took to create/write; even if they're a hopeless speller or they can't speak English, the ACs will often provide some sort of information (even if only in their native language). A lot of genuine artists do slack off on the artist comments, but combined with any of the other telltales, this can be one more hint that you're not dealing with the genuine article.
In short: Meaningless ACs = might be stolen. (Note "might be". This is the weakest indicator on the list and shouldn't be taken as proof all by itself.)
What was that? You just noticed that the beautiful picture you found and the deviant who submitted it have no few of these indicators? What can you possibly do now?
First of all, not a one of the indicators I provided (except maybe #2 and #4) are any more than circumstantial evidence. If you don't have another URL, the original artist's name, or the deviant's confession, you need more proof to report it as stolen
1. If you find another website's URL on the image, check it out. If you find someone else's name, Google it. You might find the original image that way.
2. If you think you recognize the image, or at least the artist's style, from somewhere on dA, search for it here, even if you're not sure. If you find the original image, all to the good; if you don't, no harm done.
3. The website "TinEye.com" is an image search engine - plug in an image URL, and it will search for that image elsewhere on the web. It's good enough to provide the original images used in photomanipulations, but it's neither bulletproof nor infallible. You're not necessarily going to find the original image this way, but if you can find a copy of the image that's older than the deviation you suspect is stolen, that's proof that the deviation isn't the original work either. (Check to make sure that any image you find this way is older!) This is especially useful for art you think was taken directly from a TV show or comic.
4. If you absolutely can't find the original work or don't have time to look, but the deviation is in an absurd gallery, report it as miscategorized. At the very least, this will bring it to the attention of the Gallery Directors and help clean up the gallery it's in, and it might be recognized as stolen by someone who knows where to find the original.
5. If you really can't find the original and don't have time to look, the deviation is in the right category, and you're still convinced it's not original, please, for the love of Fella, don't fave it, don't comment on it, don't watch the deviant, don't comment on the deviant's profile, don't note them, don't acknowledge their existence at all. Not even to accuse them of art theft. Art thieves seek attention. Don't encourage them.
I know, that was a beautiful picture I just discouraged you from faving or commenting on, but hey, it was in a good cause. Besides, dA is full of brilliant legitimate artists who aren't publishing anyone's work or profiting from anyone's labor but their own. Hunt up a few of them and fave away - they deserve it!