smaller background image

Just wondering how to make browser to display the jpg 50% smaller (it gets repeated on x and y on entire website):


body { background-image:url('sheep.jpg') }


I know its best just to make it smaller in Photoshop, but I would like to know the code too.

http://www.w3schools.com/cssref/css3_pr_background-size.asp

The background-size property is supported in IE9+, Firefox 4+, Opera, Chrome, and Safari 5+.