Invalid category image path
Starting from version 2.4, Magento changed the path to the category image and thumbnail returned from database. Because of this backward incompatible change you may face with broken images in navigationpro dropdowns.
To fix this issue you need to manually open dropdown settings in navigationpro menu and find the similar code:
<img class="xs-hide sm-hide" src="{{media url=''}}/catalog/category/{{var remote_entity.thumbnail}}" />
Replace image src attribute with new value:
<img class="xs-hide sm-hide" src="{{config path='web/secure/base_url'}}{{var remote_entity.thumbnail}}" />
Save the value and check if everything is fixed on the frontend.