CSOonline has a great piece today explaining everything there is to know about the relatively new phenomenon that is image spam. Definitely worth the read if you are wondering why so many spam emails end up in your inbox instead of your junk mail folder.
Image Spam—an e-mail solicitation that uses graphical images of text to avoid filters—is not new. Recently, though, it reached an unprecedented level of sophistication and took off. A year ago, fewer than five out of 100 e-mails were image spam, according to Doug Bowers of Symantec. Today, up to 40 percent are. Meanwhile, image spam is the reason spam traffic overall doubled in 2006, according to antispam company Borderware. It is expected to keep rising.