This module provides a basic Remote Image media entity type which allows embedding of images from any remote URL. The entities are simply rendered as an tag with the src attribute set the to the URL that is saved on the entity. The limitation to this approach is that you cannot leverage Drupal Core's image styles since the images are not copied to the site's local file system. When is this useful? When you need a dead simple image embed When you want to serve images directly from a CDN

The Remote Stream Wrapper module "provides the ability to use external files with file fields without saving the files to your local files directory. Also provides a 'Remote URL' browser plugin for Media."