index.php

// Login or logout will be needed to according to current user state
  if( $fbMe ) :
    $button_url = $facebook -> getLogoutUrl();
    $button_image = "http://static.ak.fbcdn.net/rsrc.php/z2Y31/hash/cxrz4k7j.gif";
  else :
    $button_url = $facebook -> getLoginUrl();
    $button_image = "http://static.ak.fbcdn.net/rsrc.php/zB6N8/hash/4li2k73z.gif";
  endif;
  
  .....
  
  // This part will be in the HTML section
  <a href="<?php echo $button_url; ?>">
    <img src="<?php echo $button_image; ?>" border="0">
  </a>