Preloading is the action of caching an image in the browser's memory for later use.

The technique is generally used for rollover images, so that the user will not have to wait the second image to download when hovering over a rollover image.

Preloader is an object that makes the preloading of images easier.

In s@rdalya, ImageButton and ImageRollover objects use Preloader internally.

When preload method is called (this generally happens in the onload event handler of the window) all the images which are explicitly added to the object with enqueue method or implicitly added through ImageRollover and ImageButton start preloading.

This object is statically accessed. It does not have a constructor.

Adds all the arguments to the preload queue.

Starts the preload operation.