Firstly, I think it should be anime wallpapers because it's a wallpaper. Anything in the vector category I think is
the image itself vectored and people can come along and wall it. Since you have a background, there is no reason for it
to be in the vector category :) It would be a wallpaper in my opinion :P
OKay, the thumb is a bit too small for me to tell you anything but it looks like a slight gradient background and a lens
flare or some sort of lighting filter in the corner.
My suggestion is [since you can vector :P] Give him a good background. Be it a tiled roof, or whatever- and then grab
yourself a stock of a moon and cut it out. I think it'll look much better and be more beneficial to the work you
put into the vector :D [though my first idea was a forest... anyways] that's up to you :)
It'll a great addition to the RK gallery :) Great work ^_^V