Nice tool, if you move your site and got some images in post linked from the old site. Or using media manager, paste a link from another site, save the post and run the tool. Wow, you imported the image to your own server instead of hotlinked media.
Another star for placing the plugin at the right place in backend menu, Tools! Not settings or media to options.
I would give another star if this could also provide an export function, like find all media attachment in posts, zip it and save to disk.
Then a perfect combination in one place.