var imageFiles_51_31 = new Array();
imageFiles_51_31['0'] = new Array ('_images/51_.gif', '_images/51_Mouseover.gif');

function image_on_51_31 (position) {
   var doc = eval("document.image51_31" + position);
   doc.src = imageFiles_51_31[position][1];
}

function image_off_51_31 (position) {
   var doc = eval("document.image51_31" + position);
   doc.src = imageFiles_51_31[position][0];
}