I usually use jQuery to overcome this problem (because I can see it's some kind of carousel):
<script src='http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' type='text/javascript'></script>
<script type='text/javascript'>
$(document).ready(function()
{
var w = 0;
$("#MainUploadDiv .ChildUploadDiv").each(function(){ w += $(this).outerWidth(true); });
$("#MainUploadDiv").css("width",w);
});
</script>
Add this code just before tag.
Hope it helps you.
Regards,
Valy.