function loadPng(o)
{
    if(MiniSite.Browser.ie)
    {
        try
        {
            var img=o;
            var imgName=o.src.toUpperCase();
            if(imgName.substring(imgName.length-3,imgName.length)=="PNG")
            {
                var imgID=(img.id)?"id='"+img.id+"' ":"";
                var imgClass=(img.className)?"class='"+img.className+"' ":"";
                var imgTitle=(img.title)?"title='"+img.title+"' ":"title='"+img.alt+"' ";
                var imgStyle="display:inline-block;"+img.style.cssText;
                if(img.align=="left")imgStyle="float:left;"+imgStyle;
                if(img.align=="right")imgStyle="float:right;"+imgStyle;
                if(img.parentElement.href)imgStyle="cursor:hand;"+imgStyle;
                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='image');\"></span>";
                img.outerHTML=strNewHTML;
            }
        }catch(e)
        {
        }
    }
}

<div class="fl">
    <a href="http://my2010.qq.com/">
        <img src="http://mat1.gtimg.com/www/iskin09/iexpo.png" width="77" height="14" align="absmiddle"
            onload="loadPng(this)" style="margin-top: 4px; _margin-top: 2px;" />
    </a>
</div>