var imageFiles_4_13 = new Array();
imageFiles_4_13['0'] = new Array ('_images/4_Ask_the_Expert.gif', '_images/4_Ask_the_ExpertMouseover.gif');

function image_on_4_13 (position) {
   var doc = eval("document.image4_13" + position);
   doc.src = imageFiles_4_13[position][1];
}

function image_off_4_13 (position) {
   var doc = eval("document.image4_13" + position);
   doc.src = imageFiles_4_13[position][0];
}