I thought it worth mentioning that with the automatic-rearranging-of-spaces option off you can have a continuous wallpaper in Lion rather like this: which is pretty cool. For those interested, this is what I did: 1. Go to System Preferences > Mission Control and uncheck "Automatically rearrange spaces based on most recent use;" 2. Open a panorama in photoshop that is large enough and preferably has a gradual change in colour or luminosity along its width; 3. (In Photoshop) View > Show > Grid; 4. Photoshop > Preferences > Guides, Grid & Slices set Gridline Every to 25 percent and subdivisions to 4; 5. Crop to the leftmost six subdivisions and save as 1.jpg, undo and crop to middle six subdivisions and save as 2.jpg, undo and crop to rightmost subdivisions and save as 3.jpg. This way there is some overlap; 6. Assign each background its proper space.