ActionScript 2.0 :: Get Dimensions Of Loaded Image And Rescale

I have a site that allows a user to upload an image, modify the image, and then save the image to their computer. This works fine, or at least it suits me so far. This is done by uploading an image to an empty movie clip, failcont_mc, and then exporting it as a jpeg once the user is done editing the image. The empty movie clip seems to be dimensionless, which isn't a problem.

The problem lies when the user uploads a photo that has very high dimensions. I'd like to be able to upload the image, then scale it down and keep it's aspect ratio if it's too large. I only want to be able to do this if the image is too large. For example, load an image sized at 800x600 and scale it down to fit into an area that is 500x400 while keeping it's proportions in tact.

Here is an idea of what I want in steps:
1. Upload the image into empty movieclip
2. Check dimensions of the occupied movieclip (previously empty)
3. if the dimensions are above 500x400
4. then scale the movieclip down while keeping proportions in tact
5. display movieclip

The code is made up of snippets from here and there on the internet, so don't be surprised if you see something that looks familiar. On a side note, I'd like to give credit to those who have allowed their code to be used openly. All of the code works fine, I would just like to add steps 2, 3, and 4.
Imageholder: failcont_mc
In the code, I have a big white space to give an idea of where I'd like to place the code. I assume the code is executed as it is read by the flashplayer. What I have tried so far was grabbing the width and height of the "occupied" movieclip and setting them as variables. I used these variables to determine if the width or height was the larger number. Then I used the variables to make a proportion to make sure the end dimensions of the movieclip stayed within the area.

Code:
//Allow this domain
System.security.allowDomain("http://localhost/");
import flash.net.FileReference;
// The listener object listens for FileReference events.
var listener:Object = new Object();
[Code] .....