[KTBleeding]

While this isn't how I would recommend doing this, here is your answer:

#content-top { background: url('images/content-top.gif') no-repeat; height: 10px;}
#content-center { background: url('images/content-center.gif') repeat-y; }
#content-bottom { background: url('images/content-bottom.gif') no-repeat; height; 15px; }

Note: background: without a color is not valid css. To make this valid, you're either going to want to specify a color:
background: #fff url(images/blah.gif) no-repeat;

Or, you can specify the background settings separately:
background-image: url(images/blah.gif); background-repeat: no-repeat;