Until you get something elso better, try looking at the DVC pictures in the sticky at the top of this board. Right-click on the one you like and it will give you the option of using it for wallpaper.
What area of OKW are you looking for? We stayed there in October so I may have something that can work for you. If I do I'll post what I have here.
To tie you over here's a picture of the Castle that I took recently. It could be a little better but it was taken with my "portable" camera (Canon S2 IS) and not my "real" camera.