I opened an issue about the fact that users cannot select images when creating a link... or rather the UI appears to allow it, but the user uploaded image is ignored. I just tested the same process on an MBin instance and the image I wanted to use overrode the default from the URL as expected in https://kbin.melroy.org/m/testing/t/128618/Global-City-Website-Trends-Analysis-of-CMS-Usage-on-Official. I've been watching the MBin fork and the way that developer community is approaching the project in a very transparent way seems like it would be more compatible with what the Drupal community expects.
This is the image I wanted to include with the post.