John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
DailyPic - You like the Bing Picture of the Day?
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.
PhotoMapper - Photomapper is a cross-platform application for Android and iOS devices designed from the ground up to provide you with informational guides and tips on the best photo spots in the world.
Wallpaper Cycler - NuonSoft WallpaperCycler is a powerfull utility to manage all your wallpapers and to automatically cycle between your wallpapers.
Really Good Photo Spots - Really Good Photo Spots is a user-friendly iPhone app that assists photographers in locating the ideal photography spots in different corners of the world.