Add Lazy Load and Lity Lightbox to content images

We had a client who has thousands of images in their blog posts over the years.

We needed to make sure all of those images have lazy load and appear in a lightbox when clicked.

Obviously this requires you to install a lazy load plugin and a light box plugin. I recommend these:

Lazy Load: http://jquery.eisbehr.de/lazy/

Lity Lightbox: https://sorgalla.com/lity/

Now the code!