I don’t work with featured images on my personal blog since the theme doesn’t really have a place/use for it.
But I write also for another blog. And I noticed that when you add a feature image after the initial post, it wont update on Facebook.
That makes sense of course since it’s already posted and all that jazz. So, my idea is that when you reblog, that you can add a featured image and tags and such. That it gives a sort of “are you sure this is complete?” page before the reblog is actually published.