Random loaded jpeg (modified)

I’ve seen threads asking about randomly loaded jpegs etc using xml. I have a question or variation of this concept. I have an animation on my home page (a jpeg slowly moving down using a tween), I would like to randomly switch this image (jpeg) each time the page is visited or reloaded, of course using the same tween/animation of the original visit. Would like to use 5 different images, that switch out everytime the site is visited, but using the same tween.

Any thoughts on how this is done? Would I have to make seperate swf’s, if so how do I go about making them randomly appear. Any fla’s or tutorials would be great.

Thanks for any help.

PS Is the a swap function that can call a jpeg and replace the image in the beginning and end of a tween?

Trt this:http://www.kirupa.com/developer/mx/loadingrandombackground.htm
or this:http://www.actionscript.org/tutorials/advanced/Loading_random_Background/index.shtml