これを試して :-
-----jsの変更----
var $active = $('#slideshow a.active');
if ( $active.length == 0 ) $active = $('#slideshow a:last');
// use this to pull the images in the order they appear in the markup
var $next = $active.next().length ? $active.next()
: $('#slideshow a:first');
------変更はcssです-------
/*** set the width and height to match your images **/
#slideshow {
position:relative;
height:350px;
}
#slideshow a {
position:absolute;
top:0;
left:0;
z-index:8;
opacity:0.0;
}
#slideshow a.active {
z-index:10;
opacity:1.0;
}
#slideshow a.last-active {
z-index:9;
}
</style>
---htmlの変更---
<div id="slideshow">
<a href="#"> <img src="image1.jpg" alt="Slideshow Image 1" class="active" /></a>
<a href="#"> <img src="image2.jpg" alt="Slideshow Image 2" /></a>
<a href="#"> <img src="image3.jpg" alt="Slideshow Image 3" /></a>
<a href="#"> <img src="image4.jpg" alt="Slideshow Image 4" /></a>
</div>