You can say a lot of things about spammers, but you can't say they are not resourceful. Once they've seen how much of their illicit e-mail is being stopped by filters, they've soon figured out to use .gif (picture) spam format to get past the anti-spam software.

Monsters and Critics Michael Thieroff reports that almost 1/3 of today's spam is in fact pictures:

"Olaf Pursche, a security expert for the Hamburg-based magazine 'Computerbild' (Computer Image), has also noticed the jump in spam. 'Many spam filters still can't screen out image spam. That means more unwanted mail in peoples mailboxes.'

The spam filters are thrown off by the variety of the e-mails. 'The pictures are generated so that every e-mail sent is slightly different,' says Marx. This is achieved by changing the size or formatting of a picture. Even a few altered pixels can let an e-mail sidestep a filter."

Fight this new menace by filtering all e-mails with .gif attachments to your spam folder, but don't delete it automatically, as some might in fact be from your friends or co-workers. Also, when you need to send e-mails with .gif picture attachment, be wise enough to write a clear sentence or two explaining what is attached.