gistfile1.js

var i = 0;  
var slide;

function SlideShow() {
  Effect.Fade($( slide[i] ), { duration:5 }); 
  i++;
  if (i == slide.length) i = 0;
  Effect.Appear($( slide[i] ), { duration:5, afterFinish: function () { SlideShow(); } }); 
}

Event.observe(window, 'load', function() {   
    $$('#myslideshow a').each(function(image){    
      $(image).hide();
      });  
    slide =  $('myslideshow').descendants();
    Effect.Appear($( slide[0] ), { duration:1, afterFinish: function () { SlideShow(); } }); 
    });