using background images in css

[jas99villa]

Not sure how to explain what I want to do but I will have a go...

The catagory header colours can be changed in the css but can I put an image in there and if so how do I do it?

.leftBoxHeading, .centerBoxHeading, .rightBoxHeading {
padding: 3px;
font-weight: bold;
border-bottom: 1px solid #222;
background-color: #333;

That is the section of css I want to change from the background colour to an image if possible? I have even added a screen capture!