// functions for image swap in left column navigation.

function preloadImages(){
  var images = new Array(3); // change the array number to reflect the number of
   for (i=0; i < 3; i++){ // change the number of the iterations to reflect the number of images to swap
    images[i] = new Image();}
  images[0].src="/images/nav_Birds0.gif";
  images[1].src="/images/nav_Butterfly0.gif";
  images[2].src="/images/nav_Contempory0.gif";
 
  }
  
function rollOver(thisImage) {
 var endBit = thisImage.src.indexOf("0.gif");
 var imageURL = thisImage.src.substring(0,endBit);
 thisImage.src = imageURL + "1.gif";}
 
function rollOut(thisImage) {
 var endBit = thisImage.src.indexOf("1.gif");
 var imageURL = thisImage.src.substring(0,endBit);
 imageURL = imageURL + "0.gif";
 thisImage.src = imageURL;}
 
init = preloadImages()