jQuery image enlarge on click to its original size

jquery.imageEnlarge.js

/**
 * Image enlarge on click
 */
(function( $ ){

	var _settings = {
		cursor: 'crosshair',
		animationTime: 300,
		watchResize: true
	}

	var _toggleImage = function(img, ev){

		if(img.hasClass('_jquery-img-enlarged')) return;

		img.addClass('_jquery-img-enlarged');
		var $img = img.clone().addClass('_jquery-img-enlarged-copy').appendTo('body');

		$img.css({
			width: img[0].clientWidth,
			height: img[0].clientHeight,
			position: 'absolute',
			top: img.offset().top,
			left: img.offset().left
		}).animate({
			width: img[0].naturalWidth,
			height: img[0].naturalHeight
		}, _settings.animationTime).one('click', function(ev){
			ev.preventDefault();
			$img.animate({
				height: img[0].clientHeight,
				width: img[0].clientWidth
			}, _settings.animationTime, function(){
				$img.remove();
				img.removeClass('_jquery-img-enlarged');
			});
		})
	}

	$.fn.imgEnlarge = function( options ) {
		var that = this;
		if(options) $.extend(_settings, options);

		var _bindImages = function(){
			return that.each(function(index, img){
				if(img.clientWidth < img.naturalWidth){
					$(img).css({cursor: _settings.cursor});
					$(img).on('click', function(ev){
						ev.preventDefault();
						_toggleImage($(this), ev);
					});
				} else {
					$(img).css({cursor: 'default'});
					$(img).off('click');
				}
			});
		};


		if(_settings.watchResize){
			$(window).on('resize', function(){
				$('._jquery-img-enlarged-copy').remove();
				$('._jquery-img-enlarged').removeClass('_jquery-img-enlarged');
				_bindImages();
			});
		}

		return _bindImages();

	};

})( window.jQuery || window.Zepto );