WallpaperSync is a small program that watches the file you are using as your wallpaper and updates the screen whenever that file changes. Ordinarily Windows will keep showing the old version of the image until you log off or reboot. WallpaperSync forces an update to occur within a minute of the change.
This can be useful if you have a network of machines and you want to update the wallpaper on all of them from a central location. Place the file you wish to use as the wallpaper on a common server in a shared folder. Then install WallpaperSync on the client machines and point them at that file. This allows you to use the wallpaper to display a list of current events, or shots from a webcam, or any other image that might change often. Whenever the file is modified on the server the clients will detect this and update their screens to show the new image.