function popup_image(url, width, height) 
{
    ww = width + 25;
    wh = height + 25;
    window.open(url, 'img_popup' + ww + wh,'toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=no,resizable=0,width=' + ww + ',height=' + wh);
}