Rename files in subfolders

rename-files.php

<?php
   function glob_recursive($pattern, $flags = 0) {
     $files = glob($pattern, $flags);
     foreach (glob(dirname($pattern).'/*', GLOB_ONLYDIR|GLOB_NOSORT) as $dir) {
           $files = array_merge($files, glob_recursive($dir.'/'.basename($pattern), $flags));
     }
     return $files;
   }

   $root             = $_GET['root'];
   $deletedCount     = 0;
   $renamedCount     = 0;

   // Get all files in root folder
   $files = glob_recursive($root.'/*');

   for($i=0;$i<count($files);$i++) {
      if(stripos($files[$i], "Thumbs.db")) {
        unlink($files[$i]);
        $deletedCount++;
      }
      else {
        // Get file extension
        $ext = substr($files[$i], strlen($files[$i])-3,3);
        
        // Rename all .JPG files to .jpg
        if (preg_match("/(JPG)/",$ext)) {
          $filename   = substr($files[$i], 0, strlen($files[$i])-3);
          $renameFile = $filename.$ext;
          $newfile    = $filename.'jpg';
  
          if(rename($files[$i], $newfile))
             echo $filename.$ext.' renamed to '.$newfile.'<br />';
          else
             echo 'Renaming file '.$renameFile.' failed.';
  
          $renamedCount++;
        }
      }
   }
   
   echo "<br /><br /><strong>$renamedCount image files renamed.</strong> $deletedCount Thumbs.db files deleted.";
?>