We have incorporated the Colorbox lightbox feature for viewing images from the WordPress Gallery Shortcode (even the block gallery). You can now view your photos in a popup overlay viewer.

NOTE: We are planning to remove the lightbox in the next update because it does not work with actual image captions correctly (not compatible). We will be offering an alternative.

screenshot for the gallery lightbox enable setting
  • Go to Appearance > Customize > Other Options
  • Look for the Enable Gallery Lightbox setting and toggle the setting
  • Click the Publish button

UPDATE: Because the Colorbox gallery script is now gone, the alternative is to check out a free plugin called WP Featherlight. This works with the block gallery. Of course, you also have the option to use other gallery plugins if you need something more robust.