Categories image by default is shown only when you view the category page. You can configure your template (M2 or Kinabalu) to have the images to show in index page:
- Login to the back-end
- Go to Mosets Tree > Templates > Kinabalu (or M2 if that is the template you are using)
- On the right hand side of the page, you'll see a list of parameters. Set "Show Categories' images in Index" to Yes. This will display your category images in Index page.
- Click the Save icon on top right of the page to save the changes.