IconInit = function() {
  var imgs = document.getElementsByClassName('icon_image');
  $A(imgs).each(function(img){
    img.onmouseover = function(){
      var div = $(img.id + '_tooltip')
      new Effect.Appear(div);
    }.bind(img);
    img.onmouseout = function(){
      var div = $(img.id + '_tooltip')
      new Effect.Fade(div);
    }.bind(img);
  });
}
Base.addInitFunction(IconInit);