Actually. I'm guessing yes.
Because at the bottom it says "no permission", no permission from the makers.

A render edit is copying over someone's work. In this case, copywritted work.

We have no permission to take these render and edited so we could get in trouble if anyone bothered.
But since this has been around for a long time, I'm guessing no one cares.
We don't even have permission to use the characters like so.

So if you wanna get really into it, everything on this site is illegal pretty much. Even the artist when they draw Balto.

No, it is not legal. You are tracing over someone's artwork.

Personally I don't think they should be allowed at all due to the simple fact that renders are [usually poorly] traced screenshots. All though it probably is illegal [I'm not sure exactly the copyright laws - though I'm sure it's illegal in one way or another] I doubt Steet would finally decide to remove the renders.

well, people trace movie images (when drawing) and thats not illegal, is it? Anyway, it wouldn't be allowed here if it was illegal, so I don't think so