Not everything you see is necessarily original.
I am not naming names, so one would hope that this post will be taken in the vein it is being offered in - one of information, so builders can make informed decisions.
There is one texture maker in particular who is well-celebrated for their work. When the TPV policy took effect on Second Life, this maker changed their TOS to forbid use of their textures on any other grid. Well before then, I'd backed up many of their textures to my hard drive, and legitimately uploaded them to another grid (see my post here). I am not the only one who did this, and we were all worried that they would pitch a hissy.
In the meantime, I've begun creating my own textures for use on my builds, and taking advantage of some of these free texture websites that others have offered links to. Imagine my surprise when I began finding well-known elements from this texture maker's textures on other sites. Sure, they cleaned them up and ran them through a few graphics filters - but the items weren't far enough from the originals that they couldn't be traced.
Let me show you a few of the originals, followed by the derivative works, that this maker claims are original:
Now I will be the first to say that if a texture artist takes the time to take something off the web and clean it up, then charge a nominal fee for doing so, I appreciate that, and in many cases, will buy their stuff. But if you claim the work is original, charge a hefty price for it, then try to tell me where and where not to use it - especially if I can find the original SO easy - you might want to rethink things and come clean with those you've deceived.
UPDATE: An astute user has pointed out that the texture vendor in question is actually breaking the law, as follows.
From their license agreement found here:
Attention Second Life users: selling the images as textures in Second Life is not allowed (not even when you modify the images).