How to add a preloader to this xml loaded images

1

Hi, i´m using this code to load several jpgs in a row -side by side-, with no spacing between. i use it for mask the holder and then, with help from zeh tween class slide the pictures. The problem is that there is a lot of images -almost 60-, so it takes a lot of time to load. What i want to do is preload the images in order, so they appear when loaded. the first load first, then the second and so on.

You can see an example of what im trying to do here:
http://www.estudioelemental.com.ar/pdm
(you are gonna have to wait a little for the animation to finish, and for the jpg to load -this is a test with only 10 jpgs-

and the code for load the images:

var myXML:XML = new XML();
myXML.ignoreWhite = true;
myXML.onLoad = function():Void
{
    showImages(16);
}

myXML.load("gal.xml");

function showImages($cols:Number):Void
{
    // Pass a paramater so I can choose how many columns I want.
    var numCols:Number             = $cols;
    var xmlLength:Number         = myXML.firstChild.childNodes.length;
    var numRows:Number             = Math.ceil(xmlLength / numCols);
    // I define a width for the image. Higher the number adds more spacing.
    var xSpacing:Number         = 529;
    // I define a height for the image. Higher the number adds more spacing.
    var ySpacing:Number         = 0;
    var imgCount:Number            = 0;
    
    var imageHolder:MovieClip = this.createEmptyMovieClip("imageHolder", this.getNextHighestDepth());
    
    for (var i:Number = 0; i < numRows; i++)
    {
        for (var j:Number = 0; j < numCols; j++)
        {
            var xmlPath:XMLNode = myXML.firstChild.childNodes[imgCount];
            
            imageHolder._x = 0;
            imageHolder._y = 0;
            
            var ob:Object = new Object({id: i});
            
            ob.mc = imageHolder.attachMovie("image_mc", "image_mc" + imgCount, imgCount, {_x: (j * xSpacing), _y: (i * ySpacing)});
            
            ob.img = xmlPath.attributes.img;
            
            ob.mc.loadMovie(ob.img);
            
            imgCount++;
        }
    }
}

any help would be apreciated, thanks in advance.
cristian.