if (document.images) {
  image1on = new Image();
  image1on.src = "images/n4_physicians.gif";

  image2on = new Image();
  image2on.src = "images/n4_medservices.gif";
  
  image3on = new Image();
  image3on.src = "images/n4_clinical.gif";
    
  image4on = new Image();
  image4on.src = "images/n4_ourstaff.gif";
      
  image5on = new Image();
  image5on.src = "images/n4_schedule.gif";
    
  image6on = new Image();
  image6on.src = "images/n4_contactus.gif";
        
  image7on = new Image();
  image7on.src = "images/n4_resources.gif";
    
  image8on = new Image();
  image8on.src = "images/n4_home.gif";

  image1off = new Image();
  image1off.src = "images/n3_physicians.gif";

  image2off = new Image();
  image2off.src = "images/n3_medservices.gif";
      
  image3off = new Image();
  image3off.src = "images/n3_clinical.gif";
    
  image4off = new Image();
  image4off.src = "images/n3_ourstaff.gif";
      
  image5off = new Image();
  image5off.src = "images/n3_schedule.gif";
    
  image6off = new Image();
  image6off.src = "images/n3_contactus.gif"; 
          
  image7off = new Image();
  image7off.src = "images/n3_resources.gif";
    
  image8off = new Image();
  image8off.src = "images/n3_home.gif";  
      

}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}