This is original wallpaper from Windows 8 M2-M3 development period, not a fan recreation. I'm just re-saved it with paint to get rid from copyrights or another info, that MS can use to find a leaker of it.
This is a proprietary wallpaper that you saved in poor quality with Paint from somewhere else. You apparently don't realize that saving something with Paint does NOT remove the existing copyrights on it!
It's just the testing version's as I see. There's an official Video for the Windows 8 UI explanation, which freaked me out. [link] < --- Takes you to the Youtube video.
I advise you read the following FAQ's on deviantART.
FAQ #157: Can I use things created by other people in my submissions?
FAQ #257: What sort of permission do I need to use someone else's work?
FAQ #304: Do you remove copies and trace-over art?
I was already thinking about that when I red your post