Miniatura en campo personalizado en Admin Categoría

[Yeth]

He usado el código de un post del foro (Acá está el post de donde saqué el código) para crear un módulo que agregue un campo tipo archivo para subir una imagen, almacena el nombre del archivo y logra subir la imagen, mi problema es saber cómo hacer para mostrar la miniatura de la imagen en e formulario del admin, llevo todo el día partiéndome la cabeza en ello. ¿Saben cómo hacerlo?, acá está el código del módulo:

 

<?php
if (!defined('_PS_VERSION_')) {
    exit;
}

use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\FileType;
use Symfony\Component\Validator\Constraints\File;

class Jh_CustomCategoryFields extends Module {
    public function __construct()
    {
        $this->name = 'jh_customcategoryfields';
        $this->tab = 'administration';
        $this->version = '1.0.0';
        $this->author = 'RV'; // Original en: https://www.prestashop.com/forums/topic/1000477-custom-file-upload-on-symfony-admin-pages-176/
        $this->need_instance = 0;
        $this->ps_versions_compliancy = [
            'min' => '1.7',
            'max' => _PS_VERSION_
        ];
        $this->bootstrap = true;
        parent::__construct();
        $this->displayName = $this->l('Custom Admin Category Fields');
        $this->description = $this->l('Adds custom fields to admin category page');
        $this->confirmUninstall = $this->l('Are you sure you want to uninstall?');
        if (!Configuration::get('jh_customcategoryfields')) {
            $this->warning = $this->l('No name provided');
        }
    }
    public function install()
    {
        return parent::install()
            && $this->_installSql()
            && $this->registerHook('actionCategoryFormBuilderModifier')
            && $this->registerHook('actionAfterCreateCategoryFormHandler')
            && $this->registerHook('actionAfterUpdateCategoryFormHandler');
    }
    public function uninstall()
    {
        if (!parent::uninstall() 
        || !$this->_unInstallSql()
        || !Configuration::deleteByName('jh_customcategoryfields')
        ) {
            return false;
        }
        return true;
    }
    protected function _installSql()
    { 
        $sqlInstallLang = 'CREATE TABLE '._DB_PREFIX_.'category_custom_fields (
                            id_category int(10) NULL,
                            image varchar(255) NULL,
                            img_name varchar(32) NULL)';
 
        $returnSqlLang = Db::getInstance()->execute($sqlInstallLang);
 
        return $returnSqlLang; 
    }
    protected function _unInstallSql()
    { 
         $sqlInstallLang = 'DROP TABLE '._DB_PREFIX_.'category_custom_fields';
  
         $returnSqlLang = Db::getInstance()->execute($sqlInstallLang);
  
         return $returnSqlLang; 
    }
    public function hookActionCategoryFormBuilderModifier($params) 
    {
        $formBuilder = $params['form_builder'];

        $formBuilder->add('image', 
            FileType::class, [
            'label' => $this->getTranslator()->trans('Banner', [], 'Modules.jh_customcategoryfields'),
            'required' => false,
            'mapped' => false,
            'constraints' => [
                new File([
                    'mimeTypes' => [
                        'image/png',
                        'image/jpg',
                        'image/jpeg',
                    ],
                    'mimeTypesMessage' => 'Formato de imagen permitido: png, jpg, jpeg',
                ])
            ]
        ]);

        $formBuilder->add('img_name', 
            TextType::class, [
            'label' => $this->getTranslator()->trans('Image name', [], 'Modules.jh_customcategoryfields'),
            'required' => false,
            'data' => $this->getImgName($params['id'])
        ]);

        $formBuilder->setData($params['data']);
    }
    public function hookActionAfterCreateCategoryFormHandler($params)
    {
        $this->updateCategoryFields($params);
    }
    public function hookActionAfterUpdateCategoryFormHandler($params)
    {
        $this->updateCategoryFields($params);
    }
    public function updateCategoryFields($params)
    {
        $id_category = $params['id'];
        // var_dump($_FILES['category']);
        $file_name = '';
        
        if (isset($_FILES['category']['name']['image'])
            && isset($_FILES['category']['tmp_name']['image'])
            && !empty($_FILES['category']['tmp_name']['image'])) {
            $image_file = [
                'name'      => $_FILES['category']['name']['image'],
                'type'      => $_FILES['category']['type']['image'],
                'tmp_name'  => $_FILES['category']['tmp_name']['image'],
                'error'     => $_FILES['category']['error']['image'],
                'size'      => $_FILES['category']['size']['image']
            ];
            
            
            if ($error = ImageManager::validateUpload($image_file, 4000000)) {
                return $error;
            } else {
                $ext = substr($image_file['name'], strrpos($image_file['name'], '.') + 1);
                $file_name = md5($image_file['name']).'.'.$ext;
                
                // echo( dirname(__FILE__).'/../../img'.DIRECTORY_SEPARATOR.$file_name ); die();
                if (!move_uploaded_file($image_file['tmp_name'], dirname(__FILE__).'/../../img'.DIRECTORY_SEPARATOR.$file_name)) {
                    return $this->displayError($this->trans('An error occurred while attempting to upload the file.', array(), 'Admin.Notifications.Error'));
                }
            }

            //$update_images_values = true;
        }
        
        // file_put_contents('../modules/jh_customcategoryfields/test_log.txt', print_r($_FILES,true));
        $idGet = 'SELECT id_category
                    FROM '._DB_PREFIX_.'category_custom_fields
                    WHERE id_category = '.$id_category;
        if (Db::getInstance()->getValue($idGet))
        {
            $sql = 'UPDATE '._DB_PREFIX_.'category_custom_fields
                        SET img_name = "'.$params['form_data']['img_name'].'",
                        image = "'.$file_name.'"
                        WHERE id_category = '.$id_category;
        } else
        {
            $sql = 'INSERT INTO '._DB_PREFIX_.'category_custom_fields (id_category,image,img_name)
                        VALUES ('.$id_category.',
                                "'.$file_name.'",
                                "'.$params['form_data']['img_name'].'")';
        }
        
        Db::getInstance()->execute($sql);
    }
    public function getImgName($id_category)
    {
        $sqlName = 'SELECT img_name
                    FROM '._DB_PREFIX_.'category_custom_fields
                    WHERE id_category = '.$id_category;
        return Db::getInstance()->getValue($sqlName) ? Db::getInstance()->getValue($sqlName) : '';
    }
}