The bandwidth occupied by spam is increasing as spammers punt products with pictures or graphics instead of just text.

Email filtering firm SoftScan said on Monday that the average size of a spam message has increased from 6.62Kb to 11.76Kb (a rise of 77 per cent) since September last year with no sign of a let-up. Although still relatively small in size, the sheer volume of spam messages many firms receive means even a slight rise can have a significant effect.

The increased size of spam messages, to say nothing of their volume, might result in higher costs for end users forced to up their bandwidth and storage resources. In February, the global ratio of spam in email traffic was 77.8 per cent (1 in 1.29 emails), an increase of two per cent on January, according to a separate study by security services firm MessageLabs. ®