1. From the back office click Products then Settings and look for category layout.
Press +Category layout.
2. You will have to name the category layout that will be created and save.
3. Edit the category layout that was recently created to configure.
4. Press +Component to add the configuration
5. Below are the needed options to select.
Section - Body
Component type - Category drawer list
Show item images - Enabled, when disabled categories will not display images
Select Image Display - you may select which display style you prefer, circle or square and press Save.
6. Apply the category layout to main category by editing the category and selecting the correct category layout, save it and then publish.