Image spam is a kind of E-mail spam where the message text of the spam is presented as a picture in an image file. Since most modern graphical E-mail client software will render the image file by default, presenting the message image directly to the user, it is highly effective at circumventing normal E-mail filtering software.I contacted the NAA and found that what they had sent was an invitation to an event in the form of an image. When I looked closely at the image I found it did contain the details of an event in October. However, the text was difficult to read. I have suggested that the NAA include the text of such announcements in the body of the message as text, so that they will not be mistaken for a Spammer.
From: Image spam, Wikipedia, 2007
Also this will allow who are blind, or otherwise can't seen the image, to read the message. I pointed out to the NAA that failing to do this may breech the Australia's Disability Discrimination Act, as well as government guidelines. The precedent was established for web pages, but most likely applies to email as well. Filing to include the text could cost the NAA $20,000.