When you assign the MessageSource property, the TclMailMessage
component parses it and extracts all message bodies including text, html, embedded images and file attachments. When the TclMailMessage component parses images and attachments, it does not save the image and/or attachment content in to the memory. It uses external stream object provided by the OnSaveAttachment event. There is also another event - OnLoadAttachment. This event is used for obtaining the attachment source when combining new mail message. You can find a sample of using the OnSaveAttachment event in the MailProgress demo program.