Picture in Centered Pop Up Window

I’m using the centered pop up window but instead of the window opening another web page I have it set to open a picture gallery.swf.

It works but the pictures do not fill up the centered pop up window. I set the pictures in the gallery to size of the centered window. That does not work.

How do I make the picutres in my gallery.swf window filled up centered pop up window.

Help :-\