Francesco,
I appreciate your response. All of the posts I have tried to share have a featured image. I want to avoid using another plugin for something that I thought was built into the theme? Also, we are a small hobby club and do not want to invest in another plugin and have privacy concerns with a SEO plugin.
Running the FB debugger I get this message: The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.
I installed Open Graph and this may do the trick…