It’s a wordpress plugin from Theme-one. This is the official site:
https://codecanyon.net/item/the-grid-responsive-wordpress-grid-plugin/13306812
And it’s compatible with your FancyBox but… something is wrong. I need to talk with Theme-one instead? :S
This is the screen of the Global Settings of The Grid:
https://www.baldovi.net/thegrid.jpg
