function showPic(imagepath, caption)
{
    var caption = (caption == null) ? '' : caption;
    url = '/showpic.html?imagepath=' + imagepath + '&caption=' + caption;
    window.open(url,'Picture',
               'status=no,width=30,height=30' +
                ',resizable=yes,toolbar=no,location=no,menubar=no,top=' +
                (screen.height / 4) + ',left=' +
                (screen.width  / 4), 'replace');
    return false;
}