Remove extra space on bottom / Image container

Here is a partial screenshot - in edit mode, hovering the mouse over a single image shows extra space on the bottom. The blue container is uniform on the sides and top, but not the bottom.

Here is what's currently enabled in the image-edit Design mode:
- Inline Image
- Captions are turned off
- Image is stretched to span the container
- Every and all combination (to my knowledge) of these Design choices does not resolve the problem.

I'm guessing some code can get rid of it - any ideas?

Additional context:

When I open image editor, the bottom margin is conveniently correct.

However, when I apply changes. The bottom margin reappears. 😕

Can you share link to page in screenshot? We can check easier.