Three styles. Which one you choose has more effect on how a gallery reads than every other setting combined.

GridEqual tiles, optional square cropMasonryEach photo keeps its shapeListPhoto plus the fields beside it
The same photos in each of the three styles.

Grid

Equal tiles in even columns. Tidy, predictable, and the right answer for thumbnails, contact sheets and anything where the set matters more than the individual photo.

Square-crop thumbnails is on by default and only applies here. With it on, every tile is a square and photos are cropped from the centre; with it off, tiles keep each photo’s own proportions and the rows are ragged. Portraits and landscapes mixed together are what square-crop is for.

Columns run from 1 to 8 and reduce automatically on narrow screens.

Masonry

Columns of a fixed width, each photo at its natural height, stacked so there are no gaps. Nobody is cropped and the shapes of the photos do the visual work.

Masonry only looks like masonry with varied shapes. A set of photos that are all 3:2 landscape produces a tidy grid with the columns slightly out of step. That is not a bug; there is nothing to interlock.

Masonry fills column by column, so reading order goes down rather than across. For a gallery where sequence matters — a chronology, a numbered series — grid or list is clearer.

List

One row per photo, with the fields beside the picture. The layout for collections where the description is as interesting as the image: archives, catalogues, price lists, provenance.

Two arrangements:

ThumbnailA small photo on the left, text filling the rest of the row.
WideA large photo taking most of the row, text in a fixed column beside it.

Rows across sets one or two rows side by side. Two is good on wide pages with short captions; one suits long text.

Photo shape applies to the wide arrangement only and runs from a 6:1 strip through 4:1, 3:1, 21:9 and 16:9 to 4:3. It exists so a portrait photo in a wide row does not stretch to an absurd height.

In list view, caption position makes no difference — the text is always beside the photo — except that None still removes it.

Choosing

You wantUse
A neat block of thumbnails, mixed orientationsGrid, square-crop on
A portfolio where composition mattersMasonry
A catalogue with prices or descriptionsList, thumbnail
A few large photos with commentaryList, wide, one row across
A strip inside a page’s designGrid, one row, a limit, no visitor controls