static void Main(string[] args) { SmtpMessage _smtpMessage = new SmtpMessage(); string _mailserver = "smtp.office365.com"; int _mailport = 587; string _username = ""; string _password = ""; bool _usessl = false; bool _useHtml = false; string _fromName = "FromName"; string _fromAddress = "*****@*****.**"; string _toname = "ToName"; string _toaddress = "*****@*****.**"; string _bccname = "BccName"; string _bccaddress = "*****@*****.**"; string _ccname = "CcName"; string _ccaddress = "*****@*****.**"; string _replytoaddress = "*****@*****.**"; // Reply to this email if other party click on reply string _notifyonreceiptname = "Disposition-Notification-To"; string _notifyonreceiptaddress = "*****@*****.**"; // Read Message will reply to this email address string _attachfile = ""; string _subject = "This is email subject"; string _bodytext = "This is some plain text."; string _bodytextimage = "<img src=\"{0}\" alt=\"Girl in a jacket\" />"; string _bodytextimages = string.Empty; _bodytextimages += string.Format(_bodytextimage, _smtpMessage.ConvertImageToBase64String(@"")); _bodytextimages += string.Format(_bodytextimage, _smtpMessage.ConvertImageToBase64String(@"")); string _content = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\">"; _content += "<HTML><HEAD><META http-equiv=Content-Type content=\"image/jpeg; charset=iso-8859-1\">"; _content += "</HEAD><BODY><DIV><FONT face=Arial color=#ff0000 size=2>This is some html text."; _content += "</FONT><br><img src=cid:Image1 alt=\"Girl in a jacket\"></img><br><img src=cid:Image2 alt=></img></DIV></BODY></HTML>"; string _contentType = "text/html"; SmtpMessage.MailPriorities _mailPriorities = SmtpMessage.MailPriorities.High; // Sender Name and Address _smtpMessage.FromName = _fromName; _smtpMessage.FromAddress = _fromAddress; // Send To Name and Address if (string.IsNullOrWhiteSpace(_toname)) { _smtpMessage.AddRecipients(_toaddress); } else { _smtpMessage.AddRecipientsWithDisplayName(_toname, _toaddress); } // Cc if (string.IsNullOrWhiteSpace(_ccname)) { _smtpMessage.AddCC(_ccaddress); } else { _smtpMessage.AddCCWithDisplayName(_ccname, _ccaddress); } // Bcc if (string.IsNullOrWhiteSpace(_bccname)) { _smtpMessage.AddBCC(_bccaddress); } else { _smtpMessage.AddBCCWithDisplayName(_bccname, _bccaddress); } if (!string.IsNullOrWhiteSpace(_replytoaddress)) { _smtpMessage.AddReplyTo(_replytoaddress); } // Add Header // For Receipt return message if (!string.IsNullOrWhiteSpace(_notifyonreceiptaddress)) { _smtpMessage.AddHeader(_notifyonreceiptname, _notifyonreceiptaddress); } // Attach the file if (!string.IsNullOrWhiteSpace(_attachfile)) { if (System.IO.File.Exists(_attachfile)) { _smtpMessage.AddAttachments(_attachfile); } } // Body _smtpMessage.Body = _bodytext; _smtpMessage.AppendBody(_bodytextimages); // EMail will be receive as html if we client is support html format otherwise will get plain text // You can skip below AddLinkResources and AddAlternateView if your email body is html and you must set _useHtml to true // Add Linked Resource for alternate body as HTML _smtpMessage.AddLinkedResources(@"", "image/jpeg", "Image1"); _smtpMessage.AddLinkedResources(@"", "image/jpeg", "Image2"); // The alternate body as HTML if (!string.IsNullOrWhiteSpace(_content)) { _smtpMessage.AddAlternateView(_content, _contentType); } _smtpMessage.Subject = _subject; _smtpMessage.HtmlFormatted = _useHtml; _smtpMessage.Priority = _mailPriorities; string _result = _smtpMessage.Send(_mailserver, _mailport, true, _username, _password, _usessl); System.Console.WriteLine(_result); if (!string.IsNullOrWhiteSpace(_result)) { System.Console.ReadLine(); } }