Depending on how long ago you uploaded the logos to the “assets” topic, and what may have changed since, it could be the URLs are no longer valid?
i.e. if you go to the post(s) in the assets topic that you uploaded the logos to, are they displayed there OK?
Maybe try “rebuild HTML” on those posts to see if the image URLs differ from the three you used in the Settings, and if they are different, try updating them.