there are a few different ways you can add pictures or videos to your website.
There is Power Gallery which allows you to create image galleries and display those on your site.
In Design Extender, there is Power CMS, Power CMS Can be used to manage the content on pages of your site, It allows you to Add images to the content areas if you like.
you can also use Data Bridge to Create Data Assist pages which allow you to manage a table in your database, say for example a Products table, Your products table can contain an image column that stores the product image.
The Data Assist insert and update pages can contain file upload fields to upload images, then on the products catalog pages, you can display those images along with the product details.