Compile actionscript & images Server-side

Hi everyone,

Does anyone know how to do what this site does?

http://www.123-banner.com

You can enter text and upload images using their banner creator,
which then generates a preview for you. This can be accomplished
by sending the variable values to the swf.

What I don’t understand is how do they the compile your images
into the swf for you to download? (which happens in seconds).

I have found a way to do this using AS3 with the embed tag but I
would like to use AS2, Flash 8. The site is quite old so I am sure
they publish for flash 8…

Cheers if you can help!