Wallch 4.5 is a handy wallpaper changer that rotates your wallpapers. Here's how you can install it in Ubuntu 14.04.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each:
sudo add-apt-repository ppa:wallch/wallch-4.0
sudo apt-get update
sudo apt-get install wallch
3. Use this command to remove Wallch:
sudo apt-get remove wallch
According to Linux G:
Wallch is an open source wallpaper changer similar to Variety.
...it rotates the wallpapers you place in a folder, can be configured to set the Picture of the day from wikipedia directly on your desktop, has support for displaying a certain site on the desktop, this getting updated automatically at a given time interval, and last but not least, it has support for Wallpaper Clocks, a feature that displays a beautiful clock over your wallpaper.More at Linux G
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