var currImage;
var nextImage;
var images;
var showNextImage = function() {
  var i = 0;
  var done = false;
  images.each(function(element) {
    if (i == currImage) {
      var outFx = new Fx.Style(element, "opacity", {
        duration: 1000
      });
      outFx.start(0);
    } else if (i == nextImage) {
      var inFx = new Fx.Style(element, "opacity", {
        duration: 1000
      });
      inFx.start(1);
      done = true;
    }
    i++;
    if (done) return;
  });
  if (nextImage < images.length - 1) {
    nextImage++; 
  } else {
    nextImage = 0;
  }

  if (currImage < images.length - 1) {
    currImage++;
  } else {
    currImage = 0;
  }
};
window.addEvent('domready', function() {
  currImage = 0;
  nextImage = 1;
  images = $$("div#brands img");
  showNextImage.periodical(5000); 
});