function swapim(num, imgname) {
    if(document.images) { 
    if (!( navigator.appName.indexOf("MSIE") >=0 &&
    navigator.appVersion.indexOf("Mac") >= 0 &&
    parseFloat(navigator.appVersion) <= 4 )) {  document[imgname].src = img[num].src; }}
}

imgsrc = new Array();
imgsrc[0] = "imagens/link_biography.gif";
imgsrc[1] = "imagens/link_biography_over.gif";
imgsrc[2] = "imagens/link_contact.gif";
imgsrc[3] = "imagens/link_contact_over.gif";
imgsrc[4] = "imagens/link_links.gif";
imgsrc[5] = "imagens/link_links_over.gif";
imgsrc[6] = "imagens/icon_back.gif";
imgsrc[7] = "imagens/icon_back_over.gif";
imgsrc[8] = "imagens/icon_fullback.gif";
imgsrc[9] = "imagens/icon_fullback_over.gif";
imgsrc[10] = "imagens/icon_forward.gif";
imgsrc[11] = "imagens/icon_forward_over.gif";
imgsrc[12] = "imagens/icon_fullforward.gif";
imgsrc[13] = "imagens/icon_fullforward_over.gif";

if (document.images) {
        img = new Array();
        for (i = 0; i < imgsrc.length; i++) {
        img[i] = new Image();
        img[i].src = imgsrc[i];
    }
}