var imageFiles_4_28 = new Array();
imageFiles_4_28['0'] = new Array ('_images/4_Ask_the_Expert.gif', '_images/4_Ask_the_ExpertMouseover.gif');

function image_on_4_28 (position) {
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   doc.src = imageFiles_4_28[position][1];
}

function image_off_4_28 (position) {
   var doc = eval("document.image4_28" + position);
   doc.src = imageFiles_4_28[position][0];
}