float and wrapping

If you take a look at my latest post at http://www.jakeboum.com/ you can see an image has text wrapped around it. I am using a shadow thing in css that looks like this:

.img-shadow {
float: left;
clear:left;
background: url(/images/shadowAlpha.png) no-repeat bottom right !important;
background: url(/images/shadow.gif) no-repeat bottom right;
margin: 10px 0 0 10px !important;
margin: 10px 0 0 5px;
}

.img-shadow img {
display: block;
position: relative;
background-color: #fff;
border: 1px solid #a9a9a9;
margin: -6px 6px 6px -6px;
padding: 4px;
}

How do I make it so that the image is on it’s own line? Can I do this without altering the CSS? Because sometimes I would like it to wrap but sometimes but I don’t. Thanks for your help.