The Windows website has a selection of nature-themed desktop wallpapers, including a photograph of a sunset at Mersal Village, Saudi Arabia, and a shot of a sunrise in Tehran. Various Islam-themed wallpapers are also available at IslamicDesktop.net.
The wallpapers on IslamicDesktop.net feature Arabic themes, such as imagery of famous mosques in the region. Text overlays quote from religious scripture, some written in Arabic script and others with English translations.
Wikimedia Commons hosts photography of countries in the Arabic world suitable for desktop wallpapers, including high-resolution photographs of beaches on the Farasan Islands. Licenses placed on these images usually allow the images to be used as wallpapers on personal computers.