As a work-around, the Harvest Cache includes a little program called "client" that will let you reload stale objects as follows:
Usage: client [-nr] [-c hostname] [-p port] url -n don't print object to stdout. -r force reload. -c get object from hostname default is localhost. -p use port as a cached port number. Default is 3128.
So, if you know the URL of the inlined image you can reload it. This is not a very good solution (e.g., you need to view the source of the object to find the URL that needs to be reloaded, and then run 'client' from the shell to do the reload), but there's not much we can do to make it more convenient as long as the Web browsers don't provide better support for reloads.
% ftpget.pl - ftp.dec.com / I anonymous harvest-user@