Echo.js - simple JavaScript image lazy loading

Echo.js is a standalone JavaScript lazy-loading image micro-library. It is fast, lightweight, and uses HTML5 data-* attributes for simple. 

Lazy-loading works by only loading the assets needed when the elements 'would' be in view, which it'll get from the server for you upon request, which is automated by simply changing the image src attribute. This is also an asynchronous process which also benefits us.