All wallpapers are 2048x2048 to take advantage of third generation iPad's retina display. There also should be no watermarks on the full images. Let me know if they show up and I'll fix it.
NOTE: I'm aware that when viewing the photos on the ipad it will say the resolution is 1024x1024. In testing I've determined you are downloading the full resolution but safari is only saying 1024x1024. So you shouldn't have any issues saving directly from ipad.