How do I send an email with HTML body that has an embedded image?

public static string getEmailFile(string file)
        {
            //string filename = Session["filename"].ToString();

            Microsoft.Office.Interop.Outlook.Application app = new Microsoft.Office.Interop.Outlook.Application();

            //MailItem item = (MailItem)app.CreateItemFromTemplate(@"C:\Users\orculloj\Desktop\Sample3\" + filename, Type.Missing);
            //MailItem item = (MailItem)app.CreateItemFromTemplate(@"C:\Users\orculloj\Desktop\Sample3\Test.msg", Type.Missing);
            MailItem item = (MailItem)app.CreateItemFromTemplate(@"C:\Users\orculloj\Desktop\Sample2\20160101021244_5541.msg", Type.Missing);

            var a = item.HTMLBody;

            return a;
        }

Outlook.Application app = new Outlook.Application();

           MailItem item = (MailItem)app.CreateItemFromTemplate(@"C:\Users\orculloj\Desktop\Sample2\20160101021244_5541.msg", Type.Missing);

           string from = item.ReceivedOnBehalfOfName + "@altisource.com";

           //string body = item.HTMLBody;

           iframe1.Attributes["src"] = "Email.aspx";

           System.Net.Mail.MailMessage mailMsg = new System.Net.Mail.MailMessage();
           MailAddress mailAddress = new MailAddress(from);

           mailMsg.To.Add("JohnEmmanuel.Orcullo@altisource.com");

           mailMsg.From = mailAddress;

           // Subject and Body
           mailMsg.Subject = "Testing mail..";

           string x = "";

           mailMsg.IsBodyHtml = true;
           mailMsg.Body = getEmailFile(x);

           //SmtpMail.SmtpServer = "Internal-Mail.ascorp.com";
           SmtpClient smtpClient = new SmtpClient("Internal-Mail.ascorp.com");

           //smtpClient.EnableSsl = true;

           smtpClient.Send(mailMsg);