How to make the Prestashop 1.7 Classic (default) theme display the thumbnail uploaded for category when displayed as a subcategory.
Edit the sub category template file /themes/classic/templates/catalog/_partials/subcategories.tpl Edit the following line to make the image url point to the thumbnail image {if !empty($subcategory.image.large.url)} <img class="replace-2x" src="{$subcategory.image. small .url}" alt="{$subcategory.name|escape:'html':'UTF-8'}" loading="lazy" width="141" height="180"/> {/if}