LinkedResource imageResource = new LinkedResource(logo, "image/jpeg"); imageResource.ContentId = "mylogo"; imageResource.TransferEncoding = TransferEncoding.Base64; FileInfo logoFile = new FileInfo(logo); SmtpClient client = new SmtpClient(smtpClient, smtpPortInt); MailMessage msg = new MailMessage(); msg.To.Add(emailAddress); msg.Subject = "My subject"; string Body = "<img alt="My Logo" hspace=0 src="cid:mylogo" align=baseline border=0 > <br /> <h1>IMPORTANT NOTICE</h1>" AlternateView htmlView = AlternateView.CreateAlternateViewFromString(Body, null, "text/html"); htmlView.LinkedResources.Add(imageResource); msg.AlternateViews.Add(htmlView);