var imgM = new Array();
        imgM[0] = new Image();  imgM[0].src = "image_top/whatsnew-a.gif";
        imgM[1] = new Image();  imgM[1].src = "image_top/whatsnew-b.gif";

function Min(nam,num) {
         document.images[nam].src = imgM[num].src;
}

function Mout(nam,num) {
         document.images[nam].src = imgM[num].src;
}