$(document).ready(function() {

    $("#hd-flatt-r img:not(#flatt-phone), #mn-flatt img")
        .mouseover(function() {
            $(this).attr("src", $(this).attr("src").replace(".gif","-over.gif"));
        })
        .mouseout(function() {
            $(this).attr("src", $(this).attr("src").replace("-over.gif",".gif"));
        });

});