Well, since I had little luck here on the forum I contacted Support directly. This was their reply:
I appreciate you pointing this out. It appears the Auctiva store window images for these listings were not generated when they were imported, which typically happens automatically.
I have just initiated the command by which your Auctiva store images will be created. Once this process, which may take 2-4 hours, has been completed, these images should be visible in your Auctiva store window.
Please let me know if I can be of further assistance.
Thank you,
Auctiva Support
It took closer to 8-9 hours, but the pictures did finally show up. Seems to me if other people are having the same problem with pictures they have not used before, then the only way to fix it is to contact Support so they can resolve it.