tons on google:
http://images.google.com/images?q=nativity&hl=en&hs=aFL&lr=&client=firefox-a&rls=org.mozilla:en-US:official_s&sa=N&tab=wi&sourceid=tipimg
In case you didnt know. Right Click on image and select set as wallpaper.
Thanks. I have tried but they get so distorted or elongated.