Drupal _ How to theme search box

Theming search form with image label and image button
 
<?php
// $Id: search-theme-form.tpl.php,v 1.1 2007/10/31 18:06:38 dries Exp $
?>
<div id="search" class="container-inline">        
  <?php    
  /* remove ' this site' - probably should try more surefire way using </label> */
  $portablePath = base_path().path_to_theme();
  
  $search["search_theme_form"]= str_replace("Search this site:", '<img src="'.$portablePath.'/img/lbl_search.gif">', $search["search_theme_form"]);  
  /* Replace button input type with image  */
  $search["submit"]= str_replace('input type="submit"', 'input type="image" src="'.$portablePath.'/img/btn_search.gif"', $search["submit"]);
  
  //$search["submit"]= str_replace('input type="submit"', 'input type="image" src="'.    $portablePath.'/img/btn_search.gif" ', $search["submit"]);
  
  print $search["search_theme_form"];
  print $search["submit"];
  print $search["hidden"];
?>
</div>