I ask this seeing a little bit of both sides already. I am working on a base stock theme to base the rest of my work off of. First thing on the list is adding any image not in the style properties to there. I can understand any element that references a color that can be changed and many areas that are purely dimensions and margins for minor things dont need it. But I think anyone who has ever tried to style a dark thing runs first into all these gradients that have to be changed in css by hand. But for example the ajax progress indicator is in the style properties but other areas using the same image are "hard coded" to the css. I would think for this particular example they would all be up for an easy change in style properties.