Set any picture as wallpaper with a single-click

The easiest way of setting your own picture as a desktop wallpaper
is to click and drag the image to the desktop using the middle mouse
button (if the image is already on the desktop then click and drag it a
few inches to the left/right). On most modern mice, the middle mouse
button is the scroll-wheel, which also doubles as a third mouse button.
On the menu that appears when you release the button, click Set as
Background.
If that sounds a little too unorthodox for you (it can be hard to use the
middle mouse button), you can also use Synaptic to install the nautilus-
wallpaper package, which adds a simple Set as Wallpaper option to the
menu that appears when you right-click an image file. After installa-
tion you’ll need to log out and then in again before the option becomes
visible.