Currently Being ModeratedOct 4, 2011 5:54 AM (in response to Michael Levin)
The person receiving the e-mail must receive the e-mail through a Microsoft Exchange server with one of the virus scanning inegration options enabled. These add the attachments to the mail. The attachment is a plain text version of the mail body (which is rich text because it contains a photo). There's nothing you can do about it, the attachment is added by Exchange.