Assets are assigned to asset groups with specific asset group permissions applied. Assets that share permissions can be put in the same asset group. Asset groups determine which assets you have permission to view, order, edit, and delete, and control the security that assets require. They're created by Widen Collective admins and can be searched by users.
Categories allow you to find assets that you have permission to view based on asset group. They display for anyone with permission to see at least one asset in the category. You may see 10 assets in a category while a coworker may see 20 assets in the same category because the role you're in has permission to view additional asset groups. As long as your admin organizes roles and asset groups appropriately, you'll only see the assets you have permission to view in a category.
Categories are also created by Collective admins. If you have the Assign Assets into Categories asset group permission, you can assign assets into categories and remove them from categories. You must also have the Access Category Search permission to browse categories and the Administrate Asset Categories permission to create, delete, arrange, and manage categories.
This image may provide some guidance about how asset groups and categories differ.