The content id of the embedded object. The content id must be unique for all embedded objects.
EmailMessage msg = new EmailMessage( "mail.mycompany.com");
msg.FromAddress = "me@mycompany.com";
msg.To = "you@yourcompany.com";
msg.Subject="logo email";
//add the html bodypart
msg.HtmlBodyPart = "<b>What do you think of the cool new logo?</b><img src=cid:mylogo>";
//embed and add the embedded object
EmbeddedObject o = new EmbeddedObject();
o.Name = "logo.gif";
o.ContentID = "mylogo";
o.FilePath = "logo.gif";
msg.EmbedObject( o );
msg.Send();
Dim msg As EmailMessage = New EmailMessage("mail.mycompany.com")
msg.FromAddress = "me@mycompany.com"
msg.To = "you@yourcompany.com"
msg.Subject = "logo email"
'add the html bodypart
msg.HtmlBodyPart = "<b>What do you think of the cool new logo?</b><img src=cid:mylogo>"
'embed and add the embedded object
Dim o As EmbeddedObject = New EmbeddedObject()
o.Name = "logo.gif"
o.ContentID = "mylogo"
o.FilePath = "logo.gif"
msg.EmbedObject(o)
msg.Send()