Batch comments / starting a review does not work on images

Summary

The batch comments feature does not work for images.

Steps to reproduce

• open merge request that adds an image (for example https://gitlab.com/reproduction-group/merge-requests/merge_requests/10/diffs)
• click image to add a comment
• click Start a review button

What is the current bug behavior?

Start a review button turns grey but nothing else happens (no errors in the browser console, no requests being made).

What is the expected correct behavior?

A comment is added.