Why are there images attached to my message?
If you are using the Embedded Images feature to embed images into your message, and the images are used as a background for the message, they could be displayed as attachments in the recipient's email client.
In fact, there are email clients that simply do not support embedded images and will display all of them as attachments. It depends on whether the client software supports the MHtml standard.
For example: Gmail, Yahoo! Mail, and Outlook.com do not support embedded images.
For this reason and other reasons (e.g. they can dramatically increase the size of the message), we recommend not using embedded images, unless absolutely necessary.