Does require about 5 minutes of file editing, but totally worth it.
One thing, my file.php string that the readme file says to paste the code prior to, was different near the end than the string in the readme file indicated. I searched for just the beginning of the string, pasted the code you provided in the readme file, and it works absolutely perfectly.
This is a huge help when you have images attached to featured posts and you need to edit and re-upload the image. No more going back to the post to paste the new file URL in, and no more wasted space on the server with multiple versions of similar images. Very nice!