(I'm pasting my suggestions here as well as on Trevor's website, since people who can reply to these questions may come to wordpress but not Trevor's site.)
Three possible minor improvements to your plugin:
(a) instead of the "you can add images to your comment" text appearing after the "submit" button and the "notify me of responses to this post" checkbox, and in my case also after the cocomment 'cocobar' which appears directly under the textarea,
can yours be inserted directly under the "code allowed" line, above the textarea?
(b) enable multiple image insertion "one image per line", so if I have a collection I can copy and paste them all in one step
(c) users can already right-click images and select "copy link location" and then paste that into the comment plugin, but for most people that requires too many clicks and scrolls. In Excel and OpenOffice, there is "Paste Special" which allows you to choose if you want to paste the text or the link (...). Can something similar be done on the web?