This snippet includes all of the boilerplate code to attach a load event to an image. Provisions are included for an image already loaded into browser's cache.

jQuery - Attach load event to image

var img = new Image();
$(img)
	// set the src attribute of the new image to our image
	.attr('src', '/path/to/image.jpg')

	// once the image has loaded, execute this code
	.one('load', function () {
		// remember to place into DOM first if you need access to width & height
		// access width & height with this.width and this.height
	})

	// if there was an error loading the image, you can do something here
	.error(function () {})

	// if image is already cached in browser, trigger load manually if necessary
	// updated with code from https://gist.github.com/797120/7176db676f1e0e20d7c23933f9fc655c2f120c58
	.each(function() {
		if (this.complete || this.complete === undefined){

			// webkit hack from http://groups.google.com/group/jquery-dev/browse_thread/thread/eee6ab7b2da50e1f
			// data uri bypasses webkit log warning (thx doug jones)
			var src = this.src;
			this.src = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw==";
			this.src = src;

			$(this).trigger('load');
		}
	});