var imageFiles_iz_1 = new Array();
imageFiles_iz_1['0'] = new Array ('_images/iz_Midwest_Towers.gif', '_images/iz_Midwest_TowersMouseover.gif');

function image_on_iz_1 (position) {
   var doc = eval("document.imageiz_1" + position);
   doc.src = imageFiles_iz_1[position][1];
}

function image_off_iz_1 (position) {
   var doc = eval("document.imageiz_1" + position);
   doc.src = imageFiles_iz_1[position][0];
}