For many years Google's homepage has been very very simple. White and straight to the point. The only significant thing that has been changed has been Google's Doodles( found here). Just a couple of days ago Google allowed you to add "a favorite photo or image to the background of the Google homepage. You can choose a photo from your computer, your own Picasa Web Album or a public gallery hosted by Picasa which includes a selection of beautiful photos." Have fun and be creative customizing your homepage, if of course you use Google. [Googleblog]
1.) Go to www.google.com
2.) Find the button/Text that Says "Change background image" on the lower left hide side and click.
3.) Choose your background and walla!
4.) If you want to remove it. You will see a button like in the picture.