Как обработать тег [thumb] в dle?

 $fieldvalue = str_replace("[thumb]","zzzxxxzzz1qqqlkaq",$fieldvalue);
   $fieldvalue = str_replace("[/thumb]","zzzxxxzzz1qqqlkaaqq",$fieldvalue);
        $pattern2 = '#zzzxxxzzz1qqqlkaq(.*?)zzzxxxzzz1qqqlkaaqq#is'; 
  preg_match_all($pattern2, $fieldvalue, $okq); 
  $i=0;
  $fdsa="";
  
  while ($okq[1][$i] != "") {
      
$pizza = explode("/", $okq[1][$i]);
$fieldvaluet=$pizza[0].'/'.$pizza[1].'/'.$pizza[2].'/'.$pizza[3].'/'.$pizza[4].'/'.$pizza[5].'/thumbs/'.$pizza[6];
  $rewq='<!--TBegin:'.$okq[1][$i].'&#124;--><a href="'.$okq[1][$i].'" rel="highslide" class="highslide"><img src="'.$fieldvaluet.'" alt="'.$row['title'].'" title="'.$row['title'].'"></a><!--TEnd-->';
  $fdsa=$fdsa.' '.$rewq;
$i++;

}
  $fieldvalue=$fdsa;