Partition Size

I created a Hardware independent image Windows XP SP2, but created the image
on a 20 GB Hard Drive. I went to use the image on a PC with a 40 GB Hard
Drive and ended up losing 20 GB of space. I know I can use a scripted image
to recreate the partition to the correct size, but I was wondering if there
was a way to make my original image create a larger partition by default.