.nav a
{
display: block;
width: 98px;
height: 29px;
}
.nav img
{
width: 98px;
height: 29px;
border: 0
}
.navb a
{
display: block;
width: 97px;
height: 29px;
}
.navb img
{
width: 97px;
height: 29px;
border: 0
}

* html a:hover
{
visibility:visible
}
.nav a:hover img
{
visibility:hidden
}
.navb a:hover img
{
visibility:hidden
}
.nav1
{
background: url(images/about_us_over.jpg) no-repeat;
}
.nav2
{
background: url(images/candidates_over.jpg) no-repeat;
}
.nav3
{
background: url(images/international_over.jpg) no-repeat;
}
.nav4
{
background: url(images/contact_over.jpg) no-repeat;
}