I'm interested if it's possible to use the WP media library with external images as sources. Basically, I need the ability to add the images to the post (via meta field that stores the connected attachment ids), but also to serve images from an external server.
I'm not looking for the CDN. The external server that hosts images, will work on optimization, but also it has its own functionality with images. I'm looking for a solution to connect the external "media library" to several WP websites.