The Tiled Gallery feature in Jetpack allows you to display your image galleries in three new styles: a rectangular mosaic, a square mosaic, and a circular grid. The rectangular and square tiled layouts also have hover-over captions to save space while making captions accessible. Here are some previews:
Also, check out examples of all three layout options in this post.
To use Tiled Galleries, first make sure the module is activated in your Jetpack dashboard. Then create a new gallery with the “Tiles” option selected.
To make all of your galleried tiled by default, go to Settings → Media in your blog’s dashboard and select the box next to “Display all your gallery pictures in a cool mosaic.” Note that choosing this option makes this layout the default for all your blog’s galleries, including those you’ve previously inserted.
To learn how to add galleries and use the new layout options, see this gallery support page.
It’s worth noting that images in tiled galleries require extra-special processing, so they will be served from WordPress.com’s CDN even if the Photon module is disabled.
Define a specific width for your galleries
Tiled Galleries are built to fill your theme’s content width. You can define a specific
$content_width value by adding the following code to your theme’s
if ( ! isset( $content_width ) ) $content_width = 800;
If your theme doesn’t define a content width, Tiled Galleries will default to 500px wide. You can read more about the Content Width theme feature here.