if ($mx1pop3|$mx1imap|mx1smtp) {
  print "<IMG SRC='http://www.xxx.com/images/up.gif' WIDTH=38 HEIGHT=21>";
} else {
  print "<IMG SRC='http://www.xxx.com/images/down.gif' WIDTH=38 HEIGHT=21>";
}

##</code><code>##

if ($mxlpop3 && $mxlimap && $mxlsmtp) { 
    # Display up.gif
} else { 
    # Display down.gif
}