How can I add a background image to an ActionScript project created in Flash Builder 4.7?

I found a solution, here is the code just in case:

Create the folders "helpers\utils" and save the code below as FullScreenBackground.as

Or remove helpers.utils from the code and place anywhere you want.

to use it:

package
{
    import flash.display.Sprite;
   
    import helpers.utils.FullScreenBackground;
   
    public class AS3BackgroundTest extends Sprite
    {
        private var appBackground:FullScreenBackground = new FullScreenBackground("images/RedBG.png", 800, 600);
       
        public function AS3BackgroundTest()
        {
            stage.addChild(appBackground);
        }
    }
}

package helpers.utils
{
    import flash.display.Bitmap;
    import flash.display.Loader;
    import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.Event;
    import flash.events.IOErrorEvent;
    import flash.net.URLRequest;
   
    public class FullScreenBackground extends Sprite
    {
        private var ldr:Loader;
        private var ldrReq:URLRequest;
        private var bmp:Bitmap;
        private var minW:Number;
        private var minH:Number;
        private var stageW:Number;
        private var stageH:Number;
        private var scaler:Number;
       
        public function FullScreenBackground(_imageURL:String, _minW:Number, _minH:Number)
        {
            super();
           
            minW = _minW;
            minH = _minH;
           
            ldr = new Loader;
            ldrReq = new URLRequest(_imageURL);
           
            ldr.contentLoaderInfo.addEventListener(Event.COMPLETE, onBGimgLoaded);
            ldr.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
            this.addEventListener(Event.ADDED_TO_STAGE, onBGaddedToStage);
        }
       
        protected function onIOError(event:IOErrorEvent):void
        {
            trace("Error loading background image: " + event);
        }
       
        protected function onBGimgLoaded(event:Event):void
        {
            bmp = Bitmap(ldr.content);
            bmp.smoothing = true;
            stage.addChild(bmp);
           
            trace("onBGimgLoaded");
           
            resizeImage();
        }
       
        private function resizeImage():void
        {
            stageW = stage.stageWidth;
            stageH = stage.stageHeight;
           
            trace(stageW);
            trace(stageH);
           
            if (stageH / stageW > this.height / this.width) {
                scaler = this.width / this.height;
                this.width = stageH * scaler;
                this.height = stageH;
            } else {
                scaler = this.height / this.width;
                this.height = stageW * scaler;
                this.width = stageW;
            }
           
            this.x = (stageW / 2) - (this.width / 2);
            this.y = 0;
        }
       
        protected function onBGaddedToStage(event:Event):void
        {
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align = StageAlign.TOP_LEFT;
            stage.addEventListener(Event.RESIZE, onStageResize);
            ldr.load(ldrReq);
        }
       
        protected function onStageResize(event:Event):void
        {
            resizeImage();
        }
    }
}