Facebook Image when posting Links - Facebook Debugging

[Ryanp]

Hello - I have read articles and the markup instructions about how to have facebook pull the header photo or image tagged in the page.  But Facebook keeps using my photo from the Shopify settings in the Admin.. I would like to have facebook pull the first image from any product or page I share..   Does anybody have and documentation or links I can add to my liquid to get this working? 

Refrence page - https://developers.facebook.com/docs/sharing/webmasters#markup