A Windows client which can automatically sync Bing wallpaper to desktop daily. And run in background.
When you first open this application, it will show a window like below and start syncing latest wallpaper. You can safely close the window, the app will run in background, without even a tray icon. You can double click the exe file again to wake up the app, the window will show again. And you can close the app by click the right-bottom corner button.
It also support running at start up. Just check the check box.