var i = 1; 
var slide;

function SlideShow() {
  Effect.Fade($( slide[i] ), { duration:5 });
  i++;
  i++;
  if (i > slide.length) i = 1;
  Effect.Appear($( 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[1] ), { duration:5, afterFinish: function () { SlideShow(); } });
    });