Index.php

<?php
namespace NicolasBejean\Importer\Controller\Adminhtml\ProductImages;

use \Magento\Backend\App\Action;
use \Magento\Backend\App\Action\Context;
use \Magento\Backend\Model\View\Result\Page;
use \Magento\Framework\Controller\ResultInterface;
use \Magento\Framework\App\ResponseInterface;
use \Magento\Framework\View\Result\PageFactory;

/**
 * Class Index
 *
 * @category PHP
 * @package  NicolasBejean\Importer\Controller\Adminhtml\ProductImages
 * @author   Nicolas Béjean <nicolas@bejean.eu>
 * @license  https://github.com/nicolasbejean/importer/blob/master/licence.txt BSD Licence
 * @link     https://www.bejean.eu
 */class Index extends Action
{
    /**
     * @var PageFactory
     */
    protected $resultPageFactory;

    /**
     * Index constructor.
     *
     * @param Context $context
     * @param PageFactory $resultPageFactory
     */
    public function __construct(
        Context $context,
        PageFactory $resultPageFactory
    ) {
        parent::__construct($context);

        $this->resultPageFactory = $resultPageFactory;
    }

    /**
     * @return Page|ResponseInterface|ResultInterface
     */
    public function execute()
    {
        /** @var Page $resultPage */
        $resultPage = $this->resultPageFactory->create();
        $resultPage->getConfig()->getTitle()->prepend(__('Import Images Product'));

        return $resultPage;
    }
}