Thinking back more to when I had dial up, flash sites in general used to take a long time to load, somewhat regardless of how graphic-intensive they were once opened. Its like having kids, once you get on ADSL its so easy to forget what it was like to work daily with dial up!
I found on my last business site (totally unrelated to retouching), we were graphic-intensive but got a lot of comments in guestbook by people commending the fast loading time. We didn't use any flash though, and offered two ways to view photographs - through a main page in small format, as well as in a portfolio style (actually a shopping cart, lol) where the small picture was clickable and popped up a larger version.
On the site I'm building now, I'm having most pics an average of 100kb, and getting it by both resizing the images and compression which is averaging about an '8' in quality when doing it in
PS. I also have mentioned compression and the ability to view higher-quality images if interested.