Hello Maeve,
Thank you for your reply.
Yes, the enlarge lightbox function is working for galleries on normal pages.
Normal page: https://ltcclock.com/install-ltc-timer-add/
KB page: https://ltcclock.com/knowledgebase/ltc-timer-add-user-guide/
I have checked and confirm that the “Link to” field is set to “Media File”. Here’s the screenshot: https://www.dropbox.com/s/fx288sb4cfhi41f/Screenshot%202017-06-15%2019.30.29.png?dl=0