flash on the homepage

On the homepage of the BlogsMU theme you have this lovely option to be able to change the 420x260 image.
What I would like to do is put a flash movie in the instead of an image.

Can you tell me which file holds the code that calls the image, I'm guessing it is here that I coud replace this code with the calling of my swf.

(or if you would care to share a more concise way as to how I might do this, that would be even better.)