Image used in Chrome App Store search results

[Geohacker]

I just posted my first app to the app store yesterday.  I am able to search for it and find it on the store today, but the picture next to my app in the search results is just my icon, centered on a white background.  Other apps have a nice rectangular picture next to them.  I have uploaded all the requested images, at all sizes.  How do I get an image to display in that spot?