Another question about event.target

I set up an xml file and loader to display thumbs in my scroll pane. I think I am adding the images using the correct methods but when I want to click on a thumbnail and trace what I clicked on the output just reveals [object Loader]. I want to load the bigPic into the picHolder movieClip. I am sure there is something fundamental I am missing. Any help appreciated.


import fl.containers.ScrollPane;
import fl.controls.ScrollPolicy;
import flash.display.MovieClip;

//
var space:int = 25;//space between images
var xt:int = 0;
var yt:int = 0;
var w:int = 0;

//create a movie clip to hold the large images
var picHolder:MovieClip = new MovieClip();
addChild(picHolder);
picHolder.width=400;
picHolder.height=300
picHolder.x=10;
picHolder.y=10;

// create a movie clip to be the source for the scroll pane
var imageHolder:MovieClip = new MovieClip();
addChild(imageHolder);

//create a scrollPane and load the imageHolder into the scrollPane
var imagePane:ScrollPane = new ScrollPane();
imagePane.setSize(320, 120);
imagePane.move(10, 230);
imagePane.source = imageHolder;
addChild(imagePane);

//load XML file 
var imagesXML:XML;
var imagesXMLLoader:URLLoader = new URLLoader();
imagesXMLLoader.addEventListener(Event.COMPLETE, xmlImagesLoaded, false, 0, true);
imagesXMLLoader.addEventListener(IOErrorEvent.IO_ERROR, onIOError, false,0,true);
imagesXMLLoader.load(new URLRequest("images.xml"));

function xmlImagesLoaded(event:Event):void {
    try {
        imagesXML = XML(event.target.data);
        imagesXMLLoader.removeEventListener(Event.COMPLETE, xmlImagesLoaded);
        imagesXMLLoader.removeEventListener(IOErrorEvent.IO_ERROR, onIOError);
        for each (var pic:XML in imagesXML..pic) {
            var thumbPic:String = pic.image.toString();
            var bigPic:String = pic.bigImage.toString();
            var thumbCaption:String = pic.caption.toString();
            //trace(thumbPic);
            //trace(bigPic);
            //trace(thumbCaption);
            
            //load thumbimage
            var picloader:Loader = new Loader();
            picloader.load(new URLRequest(thumbPic));
            addChild(picloader);
            picloader.x = xt+10;
            picloader.y = yt+10;        
            

            //set text up for captions
            var myText1:TextField = new TextField();
            var format:TextFormat = new TextFormat();
            format.font = "Arial";
            format.size = 12;
            format.kerning = 0;
            //format.align = TextFormatAlign.LEFT;
            myText1.defaultTextFormat = format;
            myText1.text = thumbCaption;
            myText1.autoSize = TextFieldAutoSize.LEFT;
            myText1.x = xt+10;
            myText1.y = yt+80;
            //w = myText1.width;

            imageHolder.addChild(picloader);
            imageHolder.addChild(myText1);                

            w = 110;
            //set spacing for captions
            xt = xt+w+space;

            imagePane.update();                    
            
            imageHolder.addEventListener(MouseEvent.CLICK, getBigPic, false, 0, true);
            imageHolder.buttonMode = true;
            
        }
    } catch (err:Error) {
        trace("Could not parse loaded content as XML:
" + err.message);
    }
}

function onIOError(event:IOErrorEvent):void {
    trace("An error occured when attempting to load the XML.
" + event.text);
}

function getBigPic(event:MouseEvent):void {
    trace(event.target);    
}