A piece of spam with an embedded graphic that promises a reduced-price version of Windows Vista is doing the rounds, according to security firm Sophos.

Often, image spam is used for promoting stock pump-and-dump scams or drugs to help with weight loss and sexual performance. However, in the latest widespread campaign seen by Sophos, image spammers are offering a bargain edition of Microsoft's new operating system, Windows Vista. The spam email claims that the recipient can save $319.05 by downloading Windows Vista today.

"Approximately 30 percent of all spam now uses images to try and sneak past anti-spam filters,” said Sophos senior technology consultant Graham Cluley in a statement. “Computer users need to ensure that they have strong defences in place or they will continue to be bombarded by nuisances like this."

It is unclear whether acting upon the spam would furnish the computer user with a pirated edition of Windows Vista or simply steal their credit card details. Whatever the ruse, Sophos recommends that users do not fall into the spammer's trap.