Great clarifying question! This would be for topics without images, and also where you don’t want images to be the default used.
Here’s some examples of what a Reddit link looks like when a link to a specific comment is shared, for example. I would assume these are generated dynamically, creating Open Graph images that are directly relevant to the content being shared (e.g. in the case of Discourse, a topic title, category, tag, etc. or for a post, possibly an excepert, their username, the category, etc.)
