Having a problem =/

So I was tasked at work with creating a dynamic banner that picks at random from ones on our server, I used this script in CS4 with AS2.0 and it works fine with one hitch.

filename = [“TippmannBanner.swf”, “Tippmann98Banner.swf”];
path = “http://images.hustlepaintball.com/Flash/”;
i = filename.length;
k = Math.floor(Math.random()*i);
loadMovie(path+filename[k], movieTarget);

It makes the banners bigger than they are supposed to be, and they lose quality… any help would be much appreciated.