The init() API takes a few options
The throttle is managed by an internal function that prevents performance issues from continuous firing of window.onscroll events. Using a throttle will set a small timeout when the user scrolls and will keep throttling until the user stops. The default is 300 milliseconds.
The delay function sets the timout value for images to start load asynchronously. Ideally it's value should be low.
The imgload function is invoked whenever an image elements finishes loading. It accepts HTMLElement as an argument which is the current element that is loaded.
Function, Arguments: None
The afterload function is callback function which executes when all images have loaded. It is fired when all the image elements have the