Gallery columns don't match with other full width elements

[Axinet]

Issue Overview

Gallery with 2 columns is narrower than centered image (both blocks should match main column/paragraph width).

Steps to Reproduce (for bugs)

1. Insert centered image
2. Insert 2 column gallery
3. Switch to frontend view
4. Last gallery image ends at a different position than a single image.

All desktop browsers that show gallery (IE11 doesn't)

Expected Behavior

Gallery with should match singl image/paragraph width like in gutenberg editor in admin:

Above screnshot is from admin but problem is on frontend (see below).

Current Behavior

There is visible gap on frontend (highlighted with blue boxes)

The screen comes from Gutenberg 2.0.0 (in version 1.9 gap was twice as wide but only at right side).

Possible Solution

For 2 columns and 2 images gallery adding

.wp-block-gallery.aligncenter .blocks-gallery-image:first-child {
    margin-left:0;
}
.wp-block-gallery.aligncenter .blocks-gallery-image:last-child {
    margin-right: 0;
}

solves the issue, didn't have time to enumerate it over different settings.
Margin styles from images come from /wp-content/plugins/gutenberg/blocks/build/style.css.

Related Issues and/or PRs

Could be related to Responsive image gallery block #4035 (it also mentions .blocks-gallery-image margins, but I don't understand from provided screen and description what is really issued there).

Todos

• Tests
• Documentation