Hello, @andy,
In our demo, we added category images like this: https://postimg.cc/GHQ1QqPb and you didn’t add category images on your site. Please first simply navigate to the Dashboard >> Products >> Category >> Edit a category then add the image in it like this: https://postimg.cc/YL2wKFk5 after that check back to your issue by clearing the browser cache.
Regards 8Themes Team.