You can make use of the [lightbox] shortcode for this.
As I have checked, you image setup ready except that, please remove the
# in the HREF field of the image.
Then, assign a class to the image. Let's say the class
Once you have added the class to the image element, add a raw content element below the image then add the lighbox shortcode in it like this:
Please note that the class
the-image that you have added to the image element is the value in the
Hope this helps.