http://www.famouswhy.com/pngfix.js

1var arVersion = navigator.appVersion.split("MSIE")
2var version = parseFloat(arVersion[1])
3if ((version >= 5.5) && (document.body.filters)) {
4    for (var i = 0; i < document.images.length; i++) {
5        var img = document.images[i]
6        var imgName = img.src.toUpperCase()
7        if (imgName.substring(imgName.length - 3, imgName.length) == "PNG") {
8            var imgID = (img.id) ? "id='" + img.id + "' " : ""
9            var imgClass = (img.className) ? "class='" + img.className + "' " : ""
10            var imgTitle = (img.title) ? "title='" + img.title + "' " : "title='" + img.alt + "' "
11            var imgStyle = "display:inline-block;" + img.style.cssText
12            if (img.align == "left") imgStyle = "float:left;" + imgStyle
13            if (img.align == "right") imgStyle = "float:right;" + imgStyle
14            if (img.parentElement.href) imgStyle = "cursor:hand;" + imgStyle
15            var strNewHTML = "<span " + imgID + imgClass + imgTitle + " style=\"" + "width:" + img.width + "px; height:" + img.height + "px;" + imgStyle + ";" + "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader" + "(src=\'" + img.src + "\', sizingMethod='scale');\"></span>"
16            img.outerHTML = strNewHTML
17            i = i - 1
18        }
19    }
20}