ActionScript 3.0 :: Random Images Loading On Refreshing Website

I'm trying to load random images every time the website is refreshed. I currently have some actionscript that makes my random image appear but it appears at the top left of the screen. and the movie continues to load the very first image in the layer. So I have 2 images loading and the random image is off center.

Here is the actionscirpt:
//imports
import caurina.transitions.Tweener;
//var
var _loader:Loader = new Loader;
var _pictureArray:Array = ["1.jpg", "2.jpg", "3.jpg", "4.jpg", "5.jpg", "6.jpg", "7.jpg", "8.jpg"];
[Code] .....
The foreground portrait is random and fades in but is in the wrong spot. All of my random images are centered in the layer. And the image in the background loads since it is the first image in the layer. but it shouldn't.