Image Sides are the various sides of the images from which the customers can view such as the left side, right side, top side and so on.
Navigate to Product Designer -> Manage Image Sides; you will land on the Manage Image Sides page.
By clicking on the Add Image Sides you can add image sides and also can set the status as enabled. Click on Save and by doing so, the image side gets enabled and is displayed in the frontend.
The Image Side helps your customers to view the product from all the sides. To know about managing the Image Sides for new products navigate to this article.