Are you posting this for me or another developer because I have no idea what that is or how it can applied to Xenforo to fix broken images.
That and lets say for instance I want to edit an existing post and delete the broken images. I can't see them unless I disable the Rich Text Editor.The only benefit I can see in replacing broken images with a working image (one that indicates image no longer available) is for SEO purposes. Is this the benefit you are seeking DRE?
That could work.Sounds like you would like to fix posts that contain broken images. Perhaps a better option would be to create a script that would create a list for you that has links to all posts which contain broken images. The script could be run any time and you can fix the broken images over time until they are all fixed.