Still not working. FWIW, my FF tab says it's a 1X1 pixel image so maybe that explains it.
This really doesn't inspire confidence. Constructing CSS web styles is a highly specialized task - something I wouldn't even tackle myself. And you can't even get us a screenshot to look at.
Consider starting over with the default style and just use the style generator to change some colors around. Or use one of the published styles (but be aware they can be a pita when it comes to updating).
vBulletin 4.x Styles