This procedure concerns linking media and how images will be displayed on your website. It enables the image to enlarge when clicked on, staying on the page as opposed to going to another page where the image is stored.
TL;DR – What the settings should look like
Why the need to change?
Linking Media File rather than Attachment Page
The default settings when creating a new gallery will link media files to an Attachment Page. What this means is that when clicked you will be taken away from the article or post to a new separate page showing the larger version of the image.
This is not always desirable and so the settings in the first graphic above should be employed to ensure that the pop-up navigation window will be used.
Information about WP Featherlight plugin
WP Featherlight is a WordPress lightbox plugin for adding a minimal, high-performance, responsive jQuery lightbox to your WordPress website. At its core, WP Featherlight is a WordPress plugin wrapper for the Featherlight jQuery lightbox plugin. When installed, the plugin will automatically display all standard WordPress images and galleries in a simple, minimalistic lightbox popup.
This tutorial was created to ensure that the plugin works correctly with the appropriate settings applied when the gallery is created.