Wally

Wally is a free Mac program that lets you change your wallpaper automatically whenever you want.

You can add multiple photo sources that Wally will then use to set your wallpapers. These sources can be anything from a local folder on your computer to a photography website like Flickr or Panoramio. You can also add images manually from the menu.

From the Preferences window, you can set the time interval between each change. You can also change the border color (if necessary), the wallpaper style, and so on, or even start the program automatically.

If your desktop wallpaper is boring you, let Wally help you switch things up.