Nitrogen is a fast and lightweight desktop background browser and setter for X windows.
Install the package.
nitrogen --help for full details. The following examples will get you started:
To view and set the desired wallpaper from a specific directory recursively, run:
$ nitrogen /path/to/image/directory/
To view and set the desired wallpaper from a specific directory non-recursively, run:
$ nitrogen --no-recurse /path/to/image/directory/
To restore the chosen wallpaper during subsequent sessions, autostart the following command:
nitrogen --restore &
Freeze with dual monitors
Remove the current nitrogen configuration: 
$ rm -r ~/.config/nitrogen/