针对附件不能下载提示的改进

$forums->func->standard_error("cannotdownload");

//$forums->func->standard_error("cannotdownload");
        if(in_array($_INPUT['extension'], array( 'jpg', 'bmp', 'gif','png') )){
        $showfile='images/cannotdownload.gif';
        @header('Content-Type: '.$forums->cache['attachmenttype']['gif']['mimetype']);
                @header('Cache-control: max-age=0');
                @header('Expires: ' . gmdate("D, d M Y H:i:s", TIMENOW + 31536000) . ' GMT');
                @header('Content-Disposition: inline; filename="' . urldecode('cannotdownload.gif') . '"');
                @header('Content-Transfer-Encoding: binary');
                @header('Content-Length: ' . (string)(filesize($showfile)));
                @readfile($showfile);
            }else{
                $forums->func->standard_error("cannotdownload");
                }