combining images

[Joel Hammer]

I am trying to use combine to just join together two images of similar width
but different length. I want the resulting image to be a simple
combination of the two, top to bottom, like so:

   -------
  | Image1|
  |       |
   ------- 
and 
   -------
  | Image2|
  |       |
  |       |
   ------- 
The desired result is :

   -------
  | Image1|
  |       |
  | Image2|
  |       |
  |       |
   ------- 


Combine seems to work by overlying the second image on the first ( or
vice versa).  If you specify an offset, you wind up with image two getting
truncated. That is to say, the size of the canvas is the size of image1.

I could solve my problem if I could figure out how to increase the canvas
size of image one to accommodate image 2.


Any insight appreciated,

Joel