Hi Sam-
The quickest way to accomplish this for the entire gallery would be to switch the gallery’s Link To setting to Image File:
If you do still want your gallery to link to the Attachment Page where you see the comment form, you’ll need to disable Discussion on each image. In order to find that, look for the Screen Options drop-down menu at the top of the page, and enable Discussion.
Once that’s enabled, you’ll see the option to disable comments near the bottom of the page.