Gallery blocks have two settings: the number of columns, and whether or not images should be cropped. The default number of columns is three, and the maximum number of columns is eight. Below is a three column gallery at full width, with cropped images. Lorem ipsum dolor...

The Common category includes the following blocks: Paragraph, image, headings, list, gallery, quote, audio, cover, video. The paragraph block is the default block type.  It should not have any alignment of any kind. It should just flow like you would normally expect. Nothing fancy. Just straight...

[gallery] You can use this page to test the Theme's handling of the gallery shortcode, including the columns parameter, from 1 to 9 columns. Themes are only required to support the default setting (3 columns), so this page is entirely optional. One Column [gallery columns="1"] Two Columns [gallery columns="2"] Three Columns [gallery...