#slideshow { position:relative; width: 640px; height:400px; z-index: 1; }
#slideshow IMG {
    position:absolute;
    top:0;
    left:0;
    z-index:8;
    opacity:0.0;
}
#slideshow IMG.active {
    z-index:10;
    opacity:1.0;
}
#slideshow IMG.last-active {
    z-index:9;
}