Works with Gutenberg (5.0.3)

I tried the other similar plugins, but they had problems with Gutenberg. This worked perfectly and did a bulk job (255 posts) with no problems on a low end server.

Pro Tip: After installing, go to Tools > External image replace.

It displays all your posts that have external images, then you can select which posts you want it to process. Or you can select all posts. I ran a test on one post, then ran it on 255 posts on a hostgator shared server.

It was slow, but it worked!

Thank you to the plugin developer!