With so many images, and detailed ones at that, the filesize is always going to be on the large side. If you haven't optimised them in Fireworks maybe that's worth a try as it seems to suck a few more K out that anything else out there, much more effective than Photoshop/ImageReady certainly.
Adjusting the image compression in Flash itself can help too (right click on the imported image in the library and choose 'properties' and there's an option to override the default compression settings for individual images. Then reduce the JPG quality in the publish options, even 5% can make a marked difference to the output file size and is usually hardly visible).
Since some of the images are duplicated between the intro movie and the main site maybe you can look into creating a shared library and attach the images dynamically which would at least save on download time in the second section.