@lenovouser and I have released[nodebb-plugin-camo] Make embedded images look secure!
[nodebb-plugin-camo] Make your embeded images look secure! nodebb-plugin-camo uses a Camo SSL image proxy to make insecure assets such as posted images look secure. By using Camo, users can post insecure (http) images, and Camo will prevent mixed content ...favicon
Community (community.nodebb.org)with an internal Camo server, which should make setup much easier, and solves many of the issues here. (Although not all)