For those who are using halvar's tool (1.12): I find it often gets "stuck" on a particular image/post. One can stop & re-start the tool, but often what I find can help to "clear" the "blockage" is manually visiting the post & opening the troublesome image in one's browser. If one
then restarts halvar's tool on that thread the "sticky" image can often now be successfully downloaded.
That is: these images are generally not simply dead, merely "troublesome".
I suspect these are just symptoms of the general "flakiness" of image host sites.
