Something

function correctPNG() // correctly handle PNG transparency in Win IE 5.5 or higher.
{
  for (var i = 0; i < document.images.length; i++)
  {
    var img = document.images[i];
    var imgName = img.src.toLowerCase();
    if (imgName.substring(imgName.length-4, imgName.length) == ".png")
    {
      var src = img.src;
      var width = img.offsetWidth;
      var height = img.offsetHeight;

      img.src = rooturl + '/template/images/transparent.png';
      img.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src=\'" + src + "\', sizingMethod='scale');";
      img.width = width;
      img.height = height;
    }
  }
}
window.attachEvent("onload", correctPNG);