var imageFiles_bz_4 = new Array();
imageFiles_bz_4['0'] = new Array ('_images/bz_Mailboxes.gif', '_images/bz_MailboxesMouseover.gif');

function image_on_bz_4 (position) {
   var doc = eval("document.imagebz_4" + position);
   doc.src = imageFiles_bz_4[position][1];
}

function image_off_bz_4 (position) {
   var doc = eval("document.imagebz_4" + position);
   doc.src = imageFiles_bz_4[position][0];
}