//tests if element is a PNG image, and if so fixes it
function add_png_image(element)
  {
  if (element && String(element.src).indexOf('.png')!=-1)
    {
    fix_image(element);
    element.attachEvent("onpropertychange", function(){property_changed()});
    }
  }

//applies filter and changes source to blank
function fix_image(element) 
  {
  element.runtimeStyle.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+element.src+"')";
  element.src='images/0.gif';
  }

//if property "src" is changed fixs image (not if it is changed to blank though)
function property_changed() 
  {
  var element=event.srcElement;

  if (event.propertyName!='src') 
    return;
  
  if (String(element.src).indexOf('images/0.gif')==-1)
    fix_image(element);
  }