if (document.images)
   {
     image_off= new Image();
     image_off.src="images/pic1.gif";
     
	 image1= new Image();
     image1.src="images/windowcat_s.jpg";
        
   }

function change1(picName,imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + ".src");
      document[picName].src= imgOn;
    }
 }