Image Spam as a Percentage of All Spam

During the first half of 2007, 27% of all spam blocked consisted of image spam. While image spam started at a higher level at the beginning of the period, reaching nearly 50% of all spam in the first week of January, it showed a marked decline beginning in April and continuing throughout May. The January level is likely due in large part to the rise of the Peacomm Trojan, which sent image spam. While the decline of image spam subsided in June, it did not regain the prominence it achieved at the beginning of the period.

Source: Symantec Internet Security Threat Report, Vol. XII