#contenitore {
    position:relative;
    width:500px;
    height:138px;
	margin:auto;
    color:#000000;
    background-color:transparent;
    z-index:100;
}

#contenitore a.miniatura, #contenitore a.miniatura:visited {
    width:450px;
    height:118px;
    background-color:trasparent;
    color:#000000;
    text-decoration:none;
}

#contenitore a.miniatura:hover, #contenitore a.miniatura:active{
    text-decoration:none;
    color:#000000;
    background-color:transparent;
}

#contenitore a .img_grande, #contenitore a .img_grande:visited{
    position:absolute;
    color:#000000;
    background-color:transparent;
    width:0px;
    height:0px;
    top:-0px;
    left:-0px;
}

#contenitore a.miniatura:hover .img_grande, #contenitore a.miniatura:active .img_grande{
    position:absolute;
    width:500px;
    height:138px;
}

#contenitore a img {
    border:0;
}