Particularly FB posts gain much more attraction via an image.
Ideally scan referenced entity for image(s). Add selection dialogue for either choosing from scan results or from media library. Post including og:image tag.
Closed: won't fix
4.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
This is something that should be done through metatag configuration on your site. That is what facebook reads and since there is a module for that, that is what I suggest doing. I don't want to bloat this module with out of scope features.