I manage a site for our Video Game publishing company that has individual game posts with a Featured Image at the top of each. In other areas of the site ("Top Games", "All Games", "Coming Soon", "Latest Releases"), you see a preview / thumbnail of that featured image. Without making any changes to the code, these preview images show up now as blue question mark boxes. See link:
I know the image is there because you can click on the box and it takes you to the game post where you can see the featured image. Some help would be much appreciated.