Flash Catalog Images Cache Magento2
To flash the Catalog Images cache, first of all instantiate the Object and Event Manager in your constructor
private $objectManager;
private $eventManager;
public function __construct(
    \Magento\Framework\ObjectManagerInterface  $objectManager,
    \Magento\Framework\Event\Manager $eventManager
){
     $this->objectManager = $objectManager;
        $this->eventManager = $eventManager;
 }
After that you can clean the catalog images cache by using this two code lines
$this->objectManager->create(\Magento\Catalog\Model\Product\Image::class)->clearCache();
$this->eventManager->dispatch('clean_catalog_images_cache_after');
to have full review have a look at this controller
\Magento\Backend\Controller\Adminhtml\Cache\CleanImages