You know what? I actually don't know. (For that one, anyway) Its weird... yesterday, I was messing around in Photoshop trying to fix my sig so I could use it again without breaking the sig limit, and while searching for the sig, I found this wallpaper hidden in a random section of my computer. I don't even recall getting this wallpaper at all.
I was thinking about uploading my entire wallpaper folder to MegaUpload or something and sharing it on GBAtemp. I haven't done it yet though, because a lot of them are from sites that want to keep it "private", so they only want the members of the site to have them. I wouldn't wanna spread around rare wallpapers without the authors' permission.