function imageSwapIn(imgID,newSrc){
   var image = document.getElementById(imgID);
   var oldSrc = image.setAttribute('oldSrc',image.src);
   image.src = newSrc;
}
function imageSwapOut(imgID){
   var image = document.getElementById(imgID);
   var oldSrc = image.getAttribute('oldSrc');
   image.src = oldSrc;
   image.removeAttribute('oldSrc');
}