images don't scale when the stack changes size

[Brian Durney]

Hello,
I am making a remote-controlled slide show program where a user uses  
a local machine to control a slide show stack on a remote machine.  I  
want to make a thumbnail version of the slide show stack so that the  
user can see what's happening on the remote machine.  I also want the  
user to be able to numerically specify a new size for the slide show  
stack.

What I tried was putting an image on each card and locking the size  
and position.  I set the Geometry to scale the image relative to the  
edges of the stack.  Then I made a button to change the size of the  
stack to the thumbnail size by setting the width and height of the  
stack.  I expected the image to scale when the stack size changed,  
but it didn't.

When I drag the resize handle of the stack, the image scales.  That  
doesn't help me, because I want to numerically specify the new size  
(e.g., 800x600), and I don't want the aspect ratio of the stack to  
change because then the images are distorted.

I have also thought of writing a loop to go through the cards and  
scale the images, but I would rather use the Geometry if that will  
work for more complicated cards (e.g., cards that have polygons,  
labels, etc.).

Please let me know if I'm missing something with the Geometry, or if  
there is another approach.
Thanks,
Brian Durney