function animate(tagId,alfa,step){
 div = document.getElementById(tagId);
 var items = new Array();

 for(c=i= 0 ;i<div.childNodes.length;i++){
  if (div.childNodes[i].tagName=="IMG"){
   items[c] = div.childNodes[i];
   c++;
  }
 }
 last = items[items.length- 1 ];
 next = items[items.length- 2 ];
 
 last.style.opacity= alfa/ 200 ;    
 last.style.filter= "progid:DXImageTransform.Microsoft.Alpha(opacity="+alfa+")";
 last.style.filter= "alpha(opacity="+alfa+")";

 if ((alfa-step)> 0 ){
 
   setTimeout("animate('"+tagId+"',"+(alfa-step)+","+step+");", 100 );
 }else{
 
  next.style.opacity=  1 ;
  next.style.filter= "progid:DXImageTransform.Microsoft.Alpha(opacity=100)";
  next.style.filter= "alpha(opacity=100)";

  tmp = last;
  div.removeChild(last);
  div.insertBefore(tmp,items[ 0 ]);
  tmp.style.opacity=  1 ;
  tmp.style.filter= "progid:DXImageTransform.Microsoft.Alpha(opacity=100)";
  tmp.style.filter= "alpha(opacity=100)";
//... , 4000 );
  setTimeout( "slideSwitch('"+tagId+"',1000)",  8000  );
 }
}

function slideSwitch(tagId,speed){
 div = document.getElementById('slideshow');
 if (div.style.visibility!="visible"){
      div.style.visibility = "visible";
 }
 items = div.getElementsByTagName('img');
 if (items.length> 0 ){
  animate(tagId, 100 , 10 );
 }
}

setTimeout( "slideSwitch('slideshow',1000);", 2000  );

--------------------------------------------------------------------
<div id="slide-container">
 <div id="slideshow">
  <img src="images/1.jpg"/>
  <img src="images/2.jpg"/>
  <img src="images/3.jpg"/>
  <img src="images/4.jpg"/>
  <img src="images/5.jpg"/>
  <img src="images/6.jpg"/>
  <img src="images/7.jpg"/>
  <img src="images/8.jpg"/>
  <img src="images/9.jpg"/>
  <img src="images/10.jpg"/>
 </div>
</div>