Informative stuff on Pump and Dump stock spamming: :
http://oddhammer.com/index.php/site/com..._youll_get_rich_buying_into_it_really/
http://www.user-groups.net/safenet/0604-22_stock_scam.html
To date (that I can find) there is no spam filter that reads and blocks the images they use in the emails, and there is no way to block the address, since the emails are bounced around all over the planet before being fed to hijacked computers and then mailed to you. The spammers use all the normal tricks as well including buying domains, spamming from them for a few days, and then abandoning them like drug dealers using disposable cellphones (burners).
As Mikey suggested, you could block all messages containing images or attachments, but that screws you up when your relatives send pictures of the new baby or something. Other than that, I found this:
http://www.spamnation.info/stocks/FAQ.html
"3.3 Is there anything I can do?
The best thing is to try to filter the spam. Unfortunately, this isn't easy. Stock spammers try particularly hard to avoid spam filters. Recently, many of them have taken to sending their messages as embedded images accompanied by random 'hashbuster' text in order to get past filtering.
If your mail program or your mail server lets you write rules that 'score' incoming messages, you might want to give higher scores to messages with embedded images. Because stock spammers make heavy use of 'botnets' - networks of hijacked home and office PCs on dialup or broadband connections - you might also want to be suspicious of messages that originate from dialup/broadband hosts. Some ISPs or mail forwarding services can flag messages that were sent directly from such hosts.
Stock spammers like forging other people's addresses in the 'From:' lines of their messages. This makes them a candidate for filtering using SPF. If you manage your own mail server, you might want to consider rejecting or flagging mail that explicitly fails an SPF test."
If anyone else can shed some light or has any ideas, please share. They are coming in faster than I can ban them all.