Thanks, I’m guessing that there is already support for images built-in to the editor, but you would have to support uploading which is generally not allowed for commenters. You could enable the feature only if the user had this capability perhaps? Then I can use it in a context where the user does have that capability. Anyway, these are ideas for the future which I think would make the plugin even better.
In the meantime I have found a solution that combines your plugin to give Comments a proper editor, combined with the “Comment Image” plugin that allows a single image to be attached per comment without the need for correct capabilities. That works well enough for the project I’m working on.