a.refer, a.refer:visited {
position:relative; 
z-index:1;
}
a.refer b {
position:absolute;
visibility:hidden; /* hide the image */
width:202px; /* give it a width */
height:152px; /* no height to solve an Opera bug that 
             makes it selectable when hidden */
border:none; /* add a border */
left:0px; /* position:the image */
top:-160px;
}
a.refer:hover {
text-decoration:none; 
border:0; /* needed for this to work in IE */ 
z-index:999;
}
a.refer:hover b {
visibility:visible; /* make the image visible */
height:0; /* now give it a height */
cursor:pointer; /* for IE */
}
a.refer:hover b img {
border:0; /* remove the link border */
}