.nav a
{
display: block;
width: 156px;
height: 16px;
}
.nav img
{
width: 156px;
height: 16px;
border: 0
}
* html a:hover
{
visibility:visible
}
.nav a:hover img
{
visibility:hidden
}
.nav1
{
background: url(images/clients_5_ov.jpg) no-repeat;
}
.nav2
{
background: url(images/clients_7_ov.jpg) no-repeat;
}
.nav3
{
background: url(images/clients_9_ov.jpg) no-repeat;
}