Admin Forum:Vertical centering of background image

i have a picture for the background image of my wiki. it's quite long, and so users with a shorter browser space (due to smaller screens or a lot of toolbars) will only ever see the top of it, which is much more plain than the center area. is there a way to set the vertical centering so the center of the image will be in the center of the screen no matter what screen size users have? (users with a larger screen will see more of the top and bottom of the image).
 * by adding the following code to MediaWiki:Wikia.css body { background-position: center center } disclaimer: didn't test it, and this t9 writing isn't for coding so might contain non-damaging errors. (: –Tm_T (Talk) 13:38, November 10, 2011 (UTC)
 * that worked perfectly, thanks very much! Sato au 13:42, November 10, 2011 (UTC)