Thanks again

      switch($image_info[2])
       {
        case 1:
         $filename .= '.gif';
         break;
        case 2:
         $filename .= '.jpg';
         break;
        case 3:
         $filename .= '.png';
         break;
  case 4:
         $filename .= '.doc';
         break;
  case 5:
         $filename .= '.pdf';
         break;
       }

I've changed the swtich to above, but still outputs false.