HELP WITH *Random Image Fading*

I have a chunk of code in AS2 that calls a random image. I’ve been trying to figure out how to add a fade to it without any luck.

Here’s the code for the RANDOM background:

function randomBG(){
    function randRange0(min:Number, max:Number):Number {
        // Generate a number between and including 20-25
        var randomNum0:Number = Math.floor(Math.random()*(max-min+1))+min;
        return randomNum0;

    // Get random number created
    var bg:Number = randRange0(20, 24);

    // Load image into holder on the stage. images should be numbered sequentially


Here’s the code for the FADE on the background (that I’ve been trying to combine):

background_mc._alpha = 0; 

background_mc.onEnterFrame = function(){
    if(background_mc._alpha == 100){
        delete background_mc.onEnterFrame;
        } else {
            background_mc._alpha += 5;

I’ve been trying to combine the two chunks of code in different ways but it ends up loading the background with an alpha of 5 (I’ve tested this by changing the number to 90/100 and it loads with almost a full alpha).

How come it is not fading in no matter where/how I put in the code? Someone please help me with an example (or the solution)…