Image not appearing in lightbox

I made a new, simple page with one image. That image is not clickable to appear in lightbox as the rest of the images on the site are. I have verified that the “disable lightbox” option is not checked. As a test, I did check that box, updated the page, then unchecked it and updated it again – no change. I don’t see a difference in any settings from this page and image to other pages on the site that do bring up the lightbox for single images, like: https://nicksdogcare.com/contact/

Any help would be appreciated. Thank you.

The page I need help with: [log in to see the link]