.imagens
{
    opacity: .6;
    filter: alpha(opacity=60);
    -moz-opacity: 0.6;
    -khtml-opacity: 0.6;
}



.imagens:hover
{
    opacity: 9.0;
    filter: alpha(opacity=900);
    -moz-opacity: 9.0;
    -khtml-opacity: 9.0;
}