Putting a background image behind featured posts

My theme came with an image slideshow for featured posts. I’d like to put a rounded corner background image behind it but am having trouble figuring out how to do it. I was trying different variations of this code (background: url(uploads/2010/07/feature_background.gif); in the stylesheet:

/** begin featured content **/
	#content .featured {
		width: 610px; height: 210px;
 		border: 3px solid #313131;
                background: url(uploads/2010/07/feature_background.gif);
		overflow: hidden;
		position: relative;
          	float: left;
                margin-top: 12px;
		margin-bottom: 12px;
		background-color: #440C1C;
	}

Any tips???

Here is my site: planetthrive.com.

Thanks!