Image spam levels have soared over the past six months, now accounting for more than half of all spam, according to new research.
Figures released by Marshal show that image spam has jumped 175 percent since September of last year, representing 56 percent of all spam sent over the past six months.
This rise in picture-based spam coincides with the decline of messages containing embedded URL links, according to the study. In 2004, 96 percent of spam messages included a website hyperlink for the recipient to click. This figure has dropped to just over half, according to the research.
Image spam is a technique used by fraudsters to bypass filters - usually set to look for common spamming words or phrases - through the use of .gif or .jpg images.
"Spammers are constantly morphing their practices to overcome anti-spam filters," said Bradley Anstis, director of product management for Marshal. "And we can expect image-spam levels to continue to increase this year."
Marshal reported a 40-percent rise in image spam during late October and early November, saying then that it accounted for 30 percent of all spam and between 15 to 20 percent of all email messages sent.