firefox, scaled images, and performance?

[Tom Horsley]

Has anyone else noticed a distinct tendency in firefox to
get hopelessly bogged down and unresponsive when it is
displaying a vary large image it has scaled to fit on the
screen, and then to become perfectly responsive once you
click on the image to display it full size?

For example:

http://www.widescreenwallpapers.in/bulkupload/widescreen/HD/Arctic%20sunrise.jpg

If I try to do a "save image as" and navigate around the
file browser to save the image in a directory it takes
a little time to navigate to, the browser gets all hung
up.

If I first click on the image to make it full size, I have
no problem navigating anywhere.

What the heck is firefox doing? Am I the only one who
sees it?