Help with creating movies and loading images into mc instances

Hi all,

This is my first attempt at using as3 and I am a little confused. I have attached my code below. Basically, I am aiming to generate 4 movie clips (mc1, mc2, mc3, mc4) and into each of those movie clips, load an image into another movie clip (mc1a, mc2a, mc3a, mc4a).

Ctrl+L shows that my movie clips are being created, but I cannot see them on the screen.

Any help would be greatly appreciated.

Thanks,
Paul

package {
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.display.Loader;
    import flash.display.LoaderInfo;
    import flash.net.URLRequest;

    // Add sprites
    public class showcase extends Sprite {
        
        public function showcase() {
            init();
        }
        
        private function init():void {
            
            var image1:String = "../images/showcase/thumb_item1.jpg";
            var image2:String = "../images/showcase/thumb_item2.jpg";
            var image3:String = "../images/showcase/thumb_item3.jpg";
            var image4:String = "../images/showcase/thumb_item4.jpg";
            
            var mc1:Sprite = new Sprite();
            var mc1a:Loader = new Loader();
            var url1:String = image1;
            var urlReq1:URLRequest = new URLRequest(url1);
            addChild(mc1);
            mc1.width = 150;
            mc1.height = 150;
            mc1.x = 0;
            mc1.y = 0;
            mc1.addChild(mc1a);
            mc1a.load(urlReq1);
            
            var mc2:Sprite = new Sprite();
            var mc2a:Loader = new Loader();
            var url2:String = image2;
            var urlReq2:URLRequest = new URLRequest(url2);
            addChild(mc2);
            mc2.width = 150;
            mc2.height = 150;
            mc2.x = 150;
            mc2.y = 0;
            mc2.addChild(mc2a);
            mc2a.load(urlReq2);
            
            var mc3:Sprite = new Sprite();
            var mc3a:Loader = new Loader();
            var url3:String = image3;
            var urlReq3:URLRequest = new URLRequest(url3);
            addChild(mc3);
            mc3.width = 150;
            mc3.height = 150;
            mc3.x = 300;
            mc3.y = 0;
            mc3.addChild(mc3a);
            mc3a.load(urlReq3);
            
            var mc4:Sprite = new Sprite();
            var mc4a:Loader = new Loader();
            var url4:String = image4;
            var urlReq4:URLRequest = new URLRequest(url4);
            addChild(mc4);
            mc4.width = 150;
            mc4.height = 150;
            mc4.x = 450;
            mc4.y = 0;
            mc4.addChild(mc4a);
            mc4a.load(urlReq4);
        }
    }
}