Just a suggestion...
It would be cool if the image pop-up limited it's size automatically to the browser window. That way you could just put any image of any size in the article, resize it for thumbnail, and when the user clicked on it, it wouldn't take up more than the screen size. If the user wanted to view the image larger than that, the pop up could have a link to download or view image in original size. I know the author could(and should) resize to a more user friendly size before upload, but this idea just adds more image options and leaves rooms for lazyness.
Anyways, I love it! Great Job!