List all images in a directory recursively.

functions.php

<?php
  function list_all_images($path)
  {
      $array = array();
      $finfo = finfo_open(FILEINFO_MIME_TYPE);
      $files = new RecursiveIteratorIterator(
          new RecursiveDirectoryIterator($path),
          RecursiveIteratorIterator::SELF_FIRST
      );

      foreach($files as $name => $file) {
          if(preg_match('/image.*/',finfo_file($finfo, $file))) {
              array_push($array, $name);
          }
      }

      return $array;
  }