/*** set the width and height to match your images **/
#slideshow {
    position:relative;
}
#slideshow IMG {
    position:absolute;
    top: 0px;
    left:0px;
    z-index:8;
    opacity:0.0;
}
#slideshow IMG.active {
    z-index:10;
    opacity:1.0;
}
#slideshow IMG.last-active {
    z-index:9;
}