magento2/app/code/Magento/Backend/Controller/Adminhtml/Cache/CleanImages.php

<?php
/**
 *
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Backend\Controller\Adminhtml\Cache;

use Magento\Framework\App\Action\HttpGetActionInterface as HttpGetActionInterface;
use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\Controller\ResultFactory;

class CleanImages extends \Magento\Backend\Controller\Adminhtml\Cache implements HttpGetActionInterface
{
    /**
     * Authorization level of a basic admin session
     *
     * @see _isAllowed()
     */
    public const ADMIN_RESOURCE = 'Magento_Backend::flush_catalog_images';

    /**
     * Clean image cache
     *
     * @return \Magento\Backend\Model\View\Result\Redirect
     */
    public function execute()
    {
        try {
            $this->_objectManager->create(\Magento\Catalog\Model\Product\Image::class)->clearCache();
            $this->_eventManager->dispatch('clean_catalog_images_cache_after');
            $this->messageManager->addSuccessMessage(__('The image cache was cleaned.'));
        } catch (LocalizedException $e) {
            $this->messageManager->addErrorMessage($e->getMessage());
        } catch (\Exception $e) {
            $this->messageManager->addExceptionMessage($e, __('An error occurred while clearing the image cache.'));
        }

        /** @var \Magento\Backend\Model\View\Result\Redirect $resultRedirect */
        $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
        return $resultRedirect->setPath('adminhtml/*');
    }
}