Regenerate images in Prestashop from command line

regenerate-images.php

<?php                                                                           
define('_PS_ROOT_DIR_', '/path/to/prestashop/root');
define('_PS_ADMIN_DIR_', _PS_ROOT_DIR_.'admin_folder');                       
                                                                                
require(_PS_ADMIN_DIR_.'/../config/config.inc.php');                            
require(_PS_ADMIN_DIR_.'/functions.php');                                       
                                                                                
class Employee2 extends EmployeeCore                                            
{                                                                               
  public function isSuperAdmin()                                                
  {                                                                             
    return true;                                                                
  }                                                                             
  public function isLoggedBack()                                                
  {                                                                             
    return true;                                                                
  }                                                                             
}                                                                               
                                                                                
class AdminImagesController extends AdminImagesControllerCore                   
{                                                                               
  function regenerate()                                                         
  {                                                                             
    $this->_regenerateThumbnails('all', true);                                  
  }                                                                             
}                                                                               
                                                                                
                                                                                
$context = Context::getContext();                                               
$context->employee = new Employee2(1);                                          
//print_r($context);                                                            
$aic = new AdminImagesController();                                             
echo "Starting regeneration\n";                                                 
$aic->regenerate();                                                             
echo "Done regenerating\n";                                                     
?>                                                                              

regenerate-images.php works on Prestashop 1.7.8.9
Thank you++++