Changing headers depending on node /path

Hi there, I was wondering whether anyone new a good way of customizing what header is loaded. Im using Marinelli theme and depending on the path (url alias / node I want it to load images for the header from a different folder. Would I be able to change this from the graphics.css -

#header {background: #000033 url(img/banners/rotate.php) no-repeat 0px 0px; /*rotates images in the banners folder */}

specifically this (img/banners/rotate.php) to an url based on the path?

Or would it be simpler to do this another way, since I may want to also change other bits such as the background colour depending on which url we're at.

Any help much appreciated

Thanks