Wallch is a General purpose Wallpaper Changer for the GNOME desktop which can change the desktop background image after an adjustable time. The aim of Wallch is to make it easier for you to keep your desktop "fresh" and new!
Some random features:
• Features JPG, PNG, GIF and BMP support
• Random image changing
• Random time changing
• Desktop/Sound notification
• History logging
• Live Earth Wallpaper
• Taking Screenshot
• Taking Webcam Image
What is new in wallch 2.0
• Statistics ( Wallpapers changed etc.. )
• Change lock screen background ( Only for Gnome 2 )
• Time Elasped until next wallpaper
• Unity Support ( Change wallpapers without opening wallch gui etc... )
• History now has a dialog
• Take Webcam Image
• Many other features and bug fixes.
Install wallch 2.0 on ubuntu
Download deb package from here once you have deb package you can double click to install them.