By default, the Lightbox window in the Gallery module will show the image title attribute's value if such attribute is being set.
Pro tip: For each image that is going to be uploaded to a WordPress website, the following attributes should always be set:
Alt Text (should always be set)
Title (should always be set)
Caption (optional)
Description (optional)
This will not only enhance SEO but also ensure crucial Accessibility attributes are present.
The Lightbox window in the Gallery module will display the Image Title when an image is opened.
Example:
How to set the attributes for images that have been already uploaded
Go to WordPress Dashboard → Media → Libary
Click on any Image.
Ensure that both the Alt Text and Title Text are set.
Demo:
