if (document.images) {

var overcold = new Image();
overcold.src = "../images/nav_overview_2.gif"
var dircold = new Image();
dircold.src = "../images/images_about/rt_nav/nav_mus_dir_2.gif"
var hourcold = new Image();
hourcold.src = "../images/images_about/rt_nav/nav_mus_hour_2.gif"
var invcold = new Image();
invcold.src = "../images/images_about/rt_nav/nav_mus_inv_2.gif"
var memcold = new Image();
memcold.src = "../images/images_about/rt_nav/nav_mus_mem_2.gif"


var overhot = new Image();
overhot.src = "../images/images_about/rt_nav/nav_overview_3.gif"
var dirhot = new Image();
dirhot.src = "../images/images_about/rt_nav/nav_mus_dir_3.gif"
var hourhot = new Image();
hourhot.src = "../images/images_about/rt_nav/nav_mus_hour_3.gif"
var invhot = new Image();
invhot.src = "../images/images_about/rt_nav/nav_mus_inv_3.gif"
var memhot = new Image();
memhot.src = "../images/images_about/rt_nav/nav_mus_mem_3.gif"


}

 function hot(imgName) {
 
           if (document.images) 
            document.images[imgName].src = eval(imgName + 'hot.src');
          
          }

 function cold(imgName) {
          
           if (document.images)
            document.images[imgName].src = eval(imgName + 'cold.src');
          
          }