I'm not sure what you're trying to say, but what it comes down to is that someone worked very hard to create an original piece of art and you've simply cut out the background and reposted it without permission or acknowledgement of the original artist. That's totally uncool.
You made a resource from someone's art. It's not like this was a promotional image put out by Ubisoft. This was a digital painting by an actual artist on Deviantart. I don't give a crap what you assume or what variations you think exist.
Cutting the background out of someone else's art and calling it a "render" or a "resource" doesn't make it suddenly okay. Whatever resource you think you're providing is only perpetuating the problem that you've created. It's not your art to create resources from, and it's certainly not cool to redistribute someone else's art without permission or credit. Just because other people do it doesn't make it not any less inappropriate. You didn't even DO anything with it. You just cut the background out and put it in another category under your own name. You say you aren't claiming it as your own, yet you're more than happy to take the compliments in the comments section as though you had anything to do with its creation.
I don't think you know what a render is. Because cutting it out of the background to make it easier to use in the creation of a signature or wallpaper is exactly what a render is. When you make a render you are not claiming it as your own, the very definition of "render" doesn't include that.
Please point out where I said thank you to any compliments. Please point out where I claimed the art as my own in the comments and how I 'take the compliments" like you say.
It doesn't matter that don't specifically claim it as your own. You're reposting someone else's art without credit or permission. That's uncool. Even worse, your defense that you're providing a resource for other people to further use that art without permission only makes what you're doing that much shadier. Calling it a "render" doesn't make it suddenly okay.
NOT TO MENTION IT ISN'T A STOCK PHOTO. You can't even put it in the right category.