I just did a few more panoramic images. The largest is 21 pictures combined to cover about 190 degrees of view. The file is just over 92mb and is 35503x2777 pixels (that is over 98 megapixels). If I printed it out at 1 foot tall, it would come out almost 13 feet long.
This is one of the frames of the panoramic image with Seattle in the distance, and the Olympic Mountains looming over Seattle, with their fresh dusting of snow.
After taking Jovino's suggestion, and using ImageMagick instead of GIMP, so I could save memory by avoiding the overhead of a gui, I've resized on of the images to 1/4 it's original size and reduce the image quality from 100% to 85%. It's not down to about 4.5Mb in size.
This one was only 19 images spliced together.
[Edit: Hmmm... Flickr wouldn't let me link to the largest version I uploaded....