What version are you running?
1.0

What steps will reproduce the problem?
1. Publish a review with a screenshot.
2. Go to the diff page, click on the screenshot to make comments on it and
make a comment and save.
3. Click Edit Review.
4. Modify the comment you entered in step 2.
5. Click Publish Review.

What is the expected output? What do you see instead?
Doing this changes the screenshot_id for the comment, causing it to point
to the incorrect image.