Flash Intro Page

I want to create a flash intro page that starts with 10-15 small images that combined make a composite image. Flash will then change the small images in a fast sequence every second or so, new images may appear and old ones leave... Total length of Flash will be 20 seconds or so and in that time, 100 images will appear and disappear, in the end, 20 images will remain, again as a composite image more details can be provided through PM