A jQuery plugin that triggers a callback after all the selected/child images have been loaded. Because you can’t do .load()on cached images.
The state of all once checked images is cached, so the calls repeated on the same images don’t have to go through a determining process for each image again. Determining might be slow in older browsers in which we have to reset src, and also might introduce image flickering.
Image state is stored in $.data associated to that particular image DOM element. That means that everything is stored per page load, so you don’t have to worry that temporarily unavailable images will be considered as broken on a next page load as well. This is just for a multiple calls within one page load.
