<https://developer.woocommerce.com/2013/03/11/editing-product-data-tabs/>
<http://schema.org/primaryImageOfPage>
<https://developer.woocommerce.com/2013/03/11/editing-product-data-tabs/#primaryimage>
<https://developer.woocommerce.com/2013/03/11/editing-product-data-tabs/>