loading pix

not completely

i am trying to be clear

i have a problem

first when you open the website on a layer i put this action :  loadMovieNum("pix1.swf", 1);

pix1.swf like pix2.swf like pix3.swf appear little by little (img1 alpha : 0% and img20 alpha : 100%)  it is why it is a .swf and not a .jpg

on the button pix1 i put this action : on (press) {loadMovieNum("pix1.swf",1);
}

on the button pix2 I put this action : on (press) {loadMovieNum("pix2.swf",1);
}

on the button pix3 I put this action : on (press) {loadMovieNum("pix3.swf",1);
}

and the problem is

for exemple when pix1.swf is loaded

and that I click on the button pix2

that load pix2.swf (a the beginig the pix is transparent (alpha: 0%) and I would like to see pix1.swf desepearing little by little

while pix2.swf is loading (you understand ?)

but not that unload pix1.swf and I see the green color of my background and that is my problem

how do I load pix2.swf without unloading pix1.swf ?

thanks in advance