[nine_k]

In Firefox, beside that, you can press Ctrl + I, open the "Media" tab, and pick any of the graphics that were already downloaded to display the page. Then you can save the picture(s) you're interested in. I suppose the source of it is the local cache.

Does not work in this particular case, of course, because the whole image is not yet in the cache.

[andersonvom]

It also works in this case, too: at some point the connection does close (if it doesn't, just hit escape) and you can save the image as usual, now from the cache.