var total_pics_num = 8;  //                        
var interval = 8000;     //                             
var time_out = 10;       //                

var i = 0;
var timeout;
var opacity = 100;

function fade_to_next()
 {
  opacity--;
  var k = i + 1;
  var image_now = 'image_' + i;

  if (i == total_pics_num)
   {
   	k = 1;
   }

  var image_next = 'image_' + k;
  document.getElementById(image_now).style.opacity = opacity/100;
  document.getElementById(image_now).style.filter = 'alpha(opacity='+ opacity +')';
  document.getElementById(image_next).style.opacity = (100-opacity)/100;
  document.getElementById(image_next).style.filter = 'alpha(opacity='+ (100-opacity) +')';


  timeout = setTimeout("fade_to_next()",time_out);
  if (opacity==1)
   {
    opacity = 100;
    clearTimeout(timeout);
   }
 }

setInterval(function() {
  i++;
  if (i > total_pics_num) i=1;
  fade_to_next();
 },interval);