Spontaneous quick post time! This being the world wide web, this topic naturally keeps coming up.
I'm gonna cut right to the case: Anybody who tells you that your files are safe from being copied while also being accessible publicly is a liar, or worse, they actually have no clue what they're talking about.
This is especially true for image files due to the technical nature via which we consume the world wide web. Anything that is displayed by any screen and is therefor viewable to its viewer can be copied in several ways and there's nothing you can do about it. Websites can implement all the safety illusions they want and advertise safety all they want but in the end it's complete bullshit.
Somebody who wants to copy your image for their own self may well go as far as snapping a picture of the screen with a camera.
Disabling browser context menus to prevent 'right-click>save as' is useless as that can be disabled via browser preferences.
Displaying images inside some special frames or under some special transparent image layers or such to fool the browser into not recognizing the actual image to thwart the aforementioned context menu 'save as' function because, get this, I'll just take a freaking screenshot or find the image via the page's media properties or I'll extract the image from the browser's own cache if I have to.
And this is just the obvious, easy ways. A skilled person could probably extract the information and reconstruct an image from a graphics card's own memory even if the image technically does not exist on the harddrive or the system memory anymore.
That brings me to the next fact. When I'm looking at an image on a web page, it's already been downloaded to my computer by the web browser. The same goes for your text, by the way.
If I can see it on my screen, it means I already have it in my possession, so to say.
This goes for every website there is.
As for deviantART specifically, here and there we make changes that make people think we don't care about art theft or even encourage.
It just needs to be said this idea is completely ridiculous, seriously. If you see a feature that could be used to steal art (save/copy an image) then you need to become aware of the complete technical picture on the matter and recognize that the mere publishing of something enables copying. That's a bare naked technical fact of the internet, the world wide web, of websites and their pages.
In the context of that fact, it doesn't matter how much you want your images to be safe from being copied (we would like that just as much) because any amount of wishing won't make it so.
I for one don't care if you want safety illusions. If we told you your images are safe while being accessibly by anyone and everyone then we'd be wrong and we'd be liars, and even if you would prefer that in order to prefer the comfort of an illusion of safety, we just won't go there.
And if we were intent of withholding features that potentially could enable the copying of content, then we'd have to go as far as reducing the site to a blank white page.
And then anyone can still copy that.
Operating under the assumption that safety illusions are of any help is of no help at all.
DeviantART is for sharing art, for people who want to share their art. Sharing means giving something away in a way or another and/or giving access to something in a way or another. DeviantART is also for collaborating, which more explicitly means exchanging of things.
Here, you share with many millions of different people and collaborate with a select few and if you feel safe with that, then you feel safe with that. But when the question of safety comes up to someone like me, I won't lie to you.
I'm well aware that people who want safety for themselves and their creations will go endless lengths to argue for safety measures, most of which are illusions, and all parties involved can argue until they die of old age, but that won't change the rather simple technical facts and reality.