<https://jeff-fried.com/dropshipping-and-print-on-demand/using-shopify-and-printful-together/#primaryimage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://jeff-fried.com/dropshipping-and-print-on-demand/using-shopify-and-printful-together/>