
The survey also found that 48 percent of those businesses surveyed said the burden on bandwidth caused by image spam is a resource problem and 42 percent admitted the exposure to malware was a concern.
“Embedding or attaching images such as .gif or .bmp files containing unwanted content into email is not new but it has grown fast and it is not being dealt with effectively," said Steve Cornish, UK sales and marketing director at PineApp.
"Spammers are always looking for new ways to bi-pass anti-spam solutions, such as attaching PDF files, and the industry is struggling to keep up."
Research carried out by Marshal earlier this year found that image spam was at an all time high, now accounting for more than half of all spam.
Researchers at the internet security firm said the rise in picture-based messages was related to the decline in emails containing embedded URL links.