ActionScript 3.0 :: Loading Images From Within Class - Alpha Mystery

I've got something very strange happening with the alpha of some loaded pictures. I load 27 images dynamically from within a class:

PHP Code:
package{
import flash.display.*;
import flash.net.URLRequest;
import flash.events.*;
public class Portrait extends Sprite{
[Code] .....

However the first 4 portraits won't change alpha to a float number, I can only set the alpha to 1.
Code:
test_portrait = new Portrait(i, 0.8, (film_width/2)-(240), white_bg_square.y);
Results in a blank screen for the first 4 portraits... All the other portraits change transparency fine. There's nothing wrong with the loaded pictures because I swapped 1 for 10 and the problem remained while image 10 in an other position changes alpha just fine.