With the premise that designers spend an inordinate time at their screens so they are likely to want calming desktop images that remind them that the sun shines, the birds buzz and the giant robots crush and destroy., we have Desktopography. Nature reinvented by invited designers and free for you to download. I was skeptical. Now I'm not. There are some damn fine images on this site and you can dig into the previous year's entries as well if you want a little retro. The packs come with size variations for your screen and some have colour options. I really like the smoking volcano desktop.