jQuery image slider - add SIMPLE thumbnail control functionality

I am using Marco's 'Background image slider' on my website. Link to background slider demo/documentation below.

(http://www.marcofolio.net/webdesign/advanced_jquery_background_image_slideshow.html)

What I want to do is add some simple thumbnail images in order to forward the user to the image in the slider they selected. Something like this < o o o o o >, and as you might imagine the second 'o' takes you to the second image and so on.

I'm trying to look for some variables or something that I can use to control the current slide but am not coming up with any luck.

Heres a copy of the plugin code

/*
* Author:      Marco Kuiper (http://www.marcofolio.net/)
*/

// Speed of the automatic slideshow
var slideshowSpeed = 6000;

// Variable to store the images we need to set as background
// which also includes some text and url's.
var photos = [ {
    "title" : "",
    "image" : "image_1.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_2.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_3.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_4.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_5.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_6.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}, {
    "title" : "",
    "image" : "image_7.jpg",
    "url" : "",
    "firstline" : "",
    "secondline" : ""
}
];



$(document).ready(function() {

// Backwards navigation
$("#back").click(function() {
    stopAnimation();
    navigate("back");
});

// Forward navigation
$("#next").click(function() {
    stopAnimation();
    navigate("next");
});

var interval;
$("#control").toggle(function(){
    stopAnimation();
}, function() {
    // Change the background image to "pause"
    $(this).css({ "background-image" : "url(img/btn_pause.png)" });

    // Show the next image
    navigate("next");

    // Start playing the animation
    interval = setInterval(function() {
        navigate("next");
    }, slideshowSpeed);
});


var activeContainer = 1;    
var currentImg = 0;
var animating = false;
var navigate = function(direction) {
    // Check if no animation is running. If it is, prevent the action
    if(animating) {
        return;
    }

    // Check which current image we need to show
    if(direction == "next") {
        currentImg++;
        if(currentImg == photos.length + 1) {
            currentImg = 1;
        }
    } else {
        currentImg--;
        if(currentImg == 0) {
            currentImg = photos.length;
        }
    }

    // Check which container we need to use
    var currentContainer = activeContainer;
    if(activeContainer == 1) {
        activeContainer = 2;
    } else {
        activeContainer = 1;
    }

    showImage(photos[currentImg - 1], currentContainer, activeContainer);

};

var currentZindex = -1;
var showImage = function(photoObject, currentContainer, activeContainer) {
    animating = true;

    // Make sure the new container is always on the background
    currentZindex--;

    // Set the background image of the new active container
    $("#headerimg" + activeContainer).css({
        "background-image" : "url(img/" + photoObject.image + ")",
        "display" : "block",
        "z-index" : currentZindex
    });

    // Hide the header text
    $("#headertxt").css({"display" : "none"});

    // Set the new header text
    $("#firstline").html(photoObject.firstline);
    $("#secondline")
        .attr("href", photoObject.url)
        .html(photoObject.secondline);
    $("#pictureduri")
        .attr("href", photoObject.url)
        .html(photoObject.title);


    // Fade out the current container
    // and display the header text when animation is complete
    $("#headerimg" + currentContainer).fadeOut(function() {
        setTimeout(function() {
            $("#headertxt").css({"display" : "block"});
            animating = false;
        }, 500);
    });
};

var stopAnimation = function() {
    // Change the background image to "play"
    $("#control").css({ "background-image" : "url(img/btn_play.png)" });

    // Clear the interval
    clearInterval(interval);
};

// We should statically set the first image
navigate("next");

// Start playing the animation
interval = setInterval(function() {
    navigate("next");
}, slideshowSpeed);

});

And a copy of the firing code in my script.js file

    //index page image preloading code
    var imgArr = new Array( // relative paths of images
        'img/image_1.jpg',
        'img/image_2.jpg',
        'img/image_3.jpg',
        'img/image_4.jpg',
        'img/image_5.jpg',
        'img/image_6.jpg',
        'img/image_7.jpg'
    );

    var preloadArr = new Array();
    var i;

    /* preload images */
    for(i=0; i < imgArr.length; i++){
        preloadArr[i] = new Image();
        preloadArr[i].src = imgArr[i];
    }

To add that functionality to the current plugin you can try this:

1. First - enable showing images by index (updated the "navigate" function in the plugin to this):

   var navigate = function(direction) {
   
       // Check if no animation is running. If it is, prevent the action
       if(animating) return;
   
       // Check which current image we need to show
       if(direction == "next") {
           currentImg++;
           if(currentImg == photos.length + 1) currentImg = 1;
       } 
       else if (direction == "back"{
           currentImg--;
           if(currentImg == 0) currentImg = photos.length;
       }
       else if (typeof direction === 'number') {
           currentImg = direction;
       }
   
       // Check which container we need to use
       var currentContainer = activeContainer;
       if(activeContainer == 1) activeContainer = 2;
       else activeContainer = 1;
   
       showImage(photos[currentImg - 1], currentContainer, activeContainer);
   };
   

2. Second - invoke the function with image index:

   $("#img1").on('click', function() {
       stopAnimation();
       navigate($(this).index());
   });