You can use the WP REST API plugin to add/manipulate/present media of a WordPress install from within your app. The page creation part I am not sure of, perhaps it’ll need to be done manually – or you can create pages via the /pages/
endpoint.
I’ll let someone correct me if I’m wrong, but the API endpoints (which are available at the link as a plugin) either made it into core already, or are really close to it.