jQuery plugin to swap new image after it loads. Useful if you want to load low res image first then swap with high res after it loads.

swapImage.js

/*
 * DWTFYW License
 * 
 * Author: Tony Brix, http://tonybrix.info
 *
 * Swap an image after it loads. Useful if you want to load low res image first then swap with high res after it loads.
 */
(function ($) {
	$.fn.swapImage = function (img) {
		var $this = this;
		var image = new Image();
		image.onload = function () {
			var src = this.src;
			$this.each(function () {
				if ($(this).is("img")) {
					this.src = src;
				} else {
					$(this).css({"background-image": "url('" + src + "')"});
				}
			});
		};
		image.src = img;
		return this;
	};
})(jQuery);