The pictures may be embedded inside the flash blob, or passed as paramaters. You might be provided the Flash blob as an editable .fla file and have to regenerate the .swf
However, for my two kopecks, I'd say:
* Intros are bad for SEO. Take the visitor right to the index page.
* Image faders are easily done with non-Flash technologies so you can edit them easily later and they work properly on mobile devices.