How to change the background image in google search engine?

This is very interesting google trick.  You can change the google background image.  This is offered by google itself.

Visit Google.com
You can see at the bottom as "Change the background Image"
Click it and sign in to your gmail account(if you already login then it is no need)
Google provides some public photos.
Why not you can upload your own photos or can select photos from picasa.


Enjoy