How to resize canvas for this image?

Question

I've watched Julianne Kost's tutorial on resizing canvas size but I can't figure out what to do with this photo.
Before you see it, here's what I'd like to achieve - white borders around this image (which is not 4x3) so that the entire image becomes 20x16.
Seems my image is only 1900x1200 so do I need to resize the image first?
Thanks for your help.

Answer 1

solved.
solution:
I have to wait till the loader finished loading and then i
can resize the image in this method.
private var loader:Loader;
private function addBgImage(base64Image:String):void{
var base64Decoder:Base64Decoder = new Base64Decoder();
base64Decoder.decode(base64Image);
var byteArray:ByteArray = base64Decoder.flush();
loader = new Loader();
loader.loadBytes( byteArray );
loader.contentLoaderInfo.addEventListener(Event.COMPLETE,
imgLoaded);
var img:Image = new Image();
img.addChild(loader);
this.addChild(img);
private function imgLoaded(event:Event):void{
loader.width = 100;
}