Actionscript 3 Load> Combine> and Save External Images - actionscript

Question

I'm new to actionscript 3, So Thank you in advance for any help you can give. Bascially what I'm trying to do is load 2 or more external images, all the same size and resolution, then combine or composite them one on top of the other, then save that result as a new image using a jpeg or png encoder.
I don't want to take a snapshot of the stage, I'd like to save the images with thier original resolution. So far the only thing I've been able to do is load two images, and composite them on the stage. thats about it.
Can someone please give some insight into how to accomplish this. I'm using flash pro CS5.5, and writing code in a class file, not on the timeline. Here is a copy of the code.
package
{
import flash.display.MovieClip;
import flash.display.Loader;
import flash.net.URLRequest;
import flash.events.*;
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.utils.ByteArray;
public class imageComposite extends MovieClip
{
var images:Array = ["koala.png","koala2.png"];//two images
public function imageComposite()
{
// constructor code
var thumbLoader:Loader;
for (var i:uint = 0; i < images.length; i++)
{
thumbLoader = new Loader;
thumbLoader.load(new URLRequest(("assets/" + images[i])));
addChild(thumbLoader);
}
thumbLoader.contentLoaderInfo.addEventListener(Event.COMPLETE,bmpData);
}
public function bmpData(evt:Event):void
{
trace("Event was completed successfully!");
}
}
}

Answer 1

First you put both the Loader objects into a separate "holder" object.
// constructor code
var holder:Sprite = new Sprite();
addChild(holder);
var thumbLoader:Loader;
for (var i:uint = 0; i < images.length; i++)
{
thumbLoader = new Loader;
thumbLoader.load(new URLRequest(("assets/" + images[i])));
holder.addChild(thumbLoader);
}
...
Later in your "complete" event handler:
var bitmapData:BitmapData = new BitmapData(holder.width, holder.height, false);
bitmapData.draw(holder);
var byteArray:ByteArray = PNGEncoder.encode(bitmapData);
Then you can write this byteArray object to the server or to disk (desktop AIR application).

Answer 2

Thank you so very much for taking the time to offer your knowledge, it was more then helpful. The code you gave me worked perfectly with one exception. the "holder" variable has to be declared outside of the function. I got alittle bit of an access error, but when I placed it outside the function it worked just fine.
Anyway, i've expanded on the code adding the ability to save. I just put a movieClip on the the stage with instance name of "saveButt_mc". Then added the ability to save using fileReference. My goal is to have it autosave to a server using php, but for now this will have to do.
Heres my final code, thanks again for the help.
-D
package
{
import flash.display.MovieClip;
import flash.display.Loader;
import flash.net.URLRequest;
import flash.events.*;
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.utils.ByteArray;
import flash.display.Sprite;
import flash.net.FileReference;
import flash.net.FileFilter;
import com.adobe.images.PNGEncoder;
public class imageComposite extends MovieClip
{
var images:Array = ["koala.png","koala2.png"];//two images
var holder:Sprite = new Sprite();
public function imageComposite()
{
// constructor code
addChild(holder);
var thumbLoader:Loader;
for (var i:uint = 0; i < images.length; i++)
{
thumbLoader = new Loader ;
thumbLoader.load(new URLRequest(("assets/" + images[i])));
holder.addChild(thumbLoader);
}
//thumbLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, bmpData);
saveButt_mc.addEventListener(MouseEvent.CLICK, bmpData);
addChild(saveButt_mc);
saveButt_mc.buttonMode = true;
}
//need contentLoaderInfo to access loader data;
public function bmpData(evt:Event):void
{
var bitmapData:BitmapData = new BitmapData(holder.width,holder.height,false);
bitmapData.draw(holder);
var byteArray:ByteArray = PNGEncoder.encode(bitmapData);
var file:FileReference = new FileReference();
file.save(byteArray, "newImage.jpg");
trace("Event was completed successfully!");
}
}
}