When someone shares my webpage on Facebook it shows my logo instead of my cover photo.  I have used the Facebook debugging tool (this link is preloaded with my website) and it tells me that:

The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.

Digging deeper into the scrapped url log , I can see that there is a whole lot of code in here that I can’t edit from my normal editor.

Please tell me how and exactly what line of HTML I need to put where in order to select a specific image to show in Facebook shares.