Flash Help

I have a flash file that I need to modify. Most of the modifications are pretty simple (like changing text). One of the changes is to add another 'frame' to the end. The flash seems to be done mostly with an action script.

I think it is a pretty simple file. It shows 4 images and they fade into each other. The images are randomly chosen from a bank of images from a folder. Unfortunately, I know almost nothing about flash and I'm having trouble making it select a fifth image. Here is the flash action script.

Here is the swf file. There are images in an image folder inside of other folders (such as 1_campus_scenic).

I have no idea if this is the best way to do the flash but this is how it was done. Thanks for any help anyone can give.