Hi there,

The short hand for the background like this:

body{
background: #ccc url(/img/pic.png) top left no-repeat;
}

the 100% is for the
bakground-position: 100%

it can also be specified in pixels (10px 200px)

this link does a better job explaining than i can..
Efficient CSS with shorthand properties | 456 Berea Street

hope this helps..
AK