if (document.images)
{
  SLIDESL.timeout = 4000 //4000 milliseconds between transitions
  SLIDESL.set_image(document.images.SLIDESIMGL);
  SLIDESL.shuffle(); //randomizes the set
  SLIDESL.update(); 
  SLIDESL.play(); //loops the show

  SLIDESR.timeout = 4000 
  SLIDESR.set_image(document.images.SLIDESIMGR);
  SLIDESR.shuffle();
  SLIDESR.update();
  SLIDESR.play();

<!-- The following ramps up the opacity of the left-side photo for Mozilla -->
var fadein_opacity = 0.04;
var fadein_img = SLIDESL.image;
function fadein(opacity) {
  if (typeof opacity != 'undefined') fadein_opacity = opacity;
  if (fadein_opacity < 0.99 && fadein_img && fadein_img.style &&
      typeof fadein_img.style.MozOpacity != 'undefined') {

    fadein_opacity += .05;
    fadein_img.style.MozOpacity = fadein_opacity;
    setTimeout("fadein()", 50);
  }
}
SLIDESL.post_update_hook = function() { fadein(0.04); }

<!-- The following ramps up the opacity of the right-side photo for Mozilla-->
var fadein_opacityR = 0.04;
var fadein_imgR = SLIDESR.image;
function fadeinR(opacity) {
  if (typeof opacity != 'undefined') fadein_opacityR = opacity;
  if (fadein_opacityR < 0.99 && fadein_imgR && fadein_imgR.style &&
      typeof fadein_imgR.style.MozOpacity != 'undefined') {

    fadein_opacityR += .05;
    fadein_imgR.style.MozOpacity = fadein_opacityR;
    setTimeout("fadeinR()", 50);
  }
}
SLIDESR.post_update_hook = function() { fadeinR(0.04); }
}