Get correct configurable product image on my order page

i am want to show correct product image on my order details page:

I am using it as:

$_item = $block->getItem();

$objectManager = MagentoFrameworkAppObjectManager::getInstance();

$_product = $objectManager->get('MagentoCatalogModelProduct')->load($_item->getProductId());

$imageHelper  = $objectManager->get('MagentoCatalogHelperImage');

$image_url = $imageHelper->init($_product, 'product_page_image_small')->setImageFile($_product->getImage())->resize(100, 100)->getUrl();

but showing main product image its not showing child product image. here i am want to show correct configurable product image.

Please help.

Thanks