Glide is a new package by Jonathan Reinink which is an on-demand image manipulation library. In this video he shows you how to set it up and the basic usage in Laravel 5.
In the tutorial Jonathan walks you through an introduction to the library and how it wraps around the Intervention image handling. He creates a basic application that, when an image endpoint is called, output the image with any given configuration options (like height and width). Glide is one of many packages making up The PHP League.