(function($) {
    $.preloadImages = function(arr) {
        $.preloadImages.add(arr);
        queuedStop = false;
        startPreloading();
    };

    $.preloadImages.add = function(arr) {
        if (typeof (arr) == 'string') {
            $.preloadImages.imageQueue.push(arr);
            return;
        }

        if (arr.length < 1) return;

        for (var i = 0, numimgs = arr.length; i < numimgs; i++) {
            if (typeof (arr[i]) == 'string')
                $.preloadImages.imageQueue.push(arr[i]);
            else if (typeof (arr[i]) == 'object' && arr[i].length > 0)
                $.preloadImages.add(arr[i]);
        }
    }

    $.preloadImages.prepend = function() {
        if (typeof (arr) == 'string') {
            $.preloadImages.imageQueue.unshift(arr);
            return;
        }

        if (arr.length < 1) return;

        for (var i = numargs - 1; i >= 0; i--) {
            if (typeof (arr[i]) == 'string')
                $.preloadImages.imageQueue.unshift(arr[i]);
            else if (typeof (arr[i]) == 'object' && arr[i].length > 0)
                $.preloadImages.prepend(arr[i]);
        }
    }
    
    $.preloadImages.clear = function() {
        $.preloadImages.imageQueue = [];
    }

    $.preloadImages.stop = function() {
        queuedStop = true;
    }

    $.preloadImages.start = function() {
        queuedStop = false;
        startPreloading();
    }
    
    $.preloadImages.imageQueue = [];

    /* PRIVATE */
    var isPreloading = false;
    var queuedStop = false;

    function startPreloading() {
        if (isPreloading)
            return;

        $(document.createElement('img')).bind('load', function() {
            if (queuedStop) {
                queuedStop = isPreloading = false;
                return;
            }
            isPreloading = true;
            if ($.preloadImages.imageQueue.length > 0) {
                this.src = $.preloadImages.imageQueue.shift();
            } else
                isPreloading = false;
        }).trigger('load');
    }
})(jQuery);