Managed email security firm SoftScan says that the surge of image-based spam - which is designed to beat most anti-spam systems - has increased the size of a typical spam message by 77 per cent since September of last year.
The result, the anti-spam specialist says, is that it will add to the cost of managing email for many organisations, as they have to scale up their bandwidth and storage requirements as a result.
Since September last year, the firm says that individual emails have increased in size from an average of 6.62 KB to 11.76 KB.
Although still relatively small in size, SoftScan says that the sheer volume of spam that many businesses receive means that even only a slight rise can have a significant effect.
Organisations that stop spam at their email servers, the the firm says, still have to pay for the bandwidth to receive it and depending on how their email back-up is configured, storage costs may rise too if spam is included in the archive.
Diego d'Ambra, SoftScan's CTO, said that the growth in file size, combined with the increasing volume of spam now means that many different aspects from network administration to Internet bandwidth are affected.
"Email file size is going to become a real headache for businesses, particularly if spammers start to use other types of medium such as audio or video files once the tactic of image spam no longer works against the majority of filters," he said...