ok, i think i got it.
on the one hand i found another solution which might be better to handle, on the other hand i've got some good reason why i think that your file didn't work as you wanted.
I found out that you didn't use movieclips that faded in and out in your fotoclip but some other type of symbol. (unfortunately i don't know what you call it in english since i work on a german version. it's the 3rd type of symbol you can make, not movieclip, not button. it's called graphic is think... i'm sure you know what i mean.)
By chance and as far as i remember correctly a few days ago i read in a flash book that graphics kind of stream when they are tweened.
that means they are not submittet one time like a movieclip and then changed in some way by a tween or what ever.
(as far as i understand the chapter) they are submitted again and again. that's why the film slows down.
the solution i'd suggest consists of two parts:
firstly you should never use graphic-symbols for tweens.
secondly i replaced your tweens by a script that will keep the filesize down.
it is some kind of timer that will fade in the clip from transparent to visible in one second
and in the next second will fade it out to total transparency again, then jump to the next image which will do the same.
the script is kept in an external file so you can easily change the duration of fading by editing the external textfile, just by opening it in the text editor.
i wrote another short desciption in the file on how to handle the script in case you can't figure it out.
and
that is where it is located at the moment since the server i usually use is down. when he is up again it will be on
and
sorry, it took me some time to script the timer correctly but i think it works now. regards
Firegambler