Private MITTENTE As String = "rossi.paolo@gmail.com"
    Private DESTINATARIO As String = "verdi.maria@gmail.com"
    Private PERCORSO_LOGO As String = "C:\img\logo.gif"
    Private USERNAME As String = "username@gmail.com"
    Private PASSWORD As String = "password@gmail.com"
    Private OGGETTO_EMAIL As String = "INVIO EMAIL IN HTML CON IMMAGINE"


    Private Sub email()
        ' Creare il messagio dell'email
        Dim email As New MailMessage(MITTENTE, DESTINATARIO)

        ' Informazioni
        email.Subject = OGGETTO_EMAIL
        email.IsBodyHtml = True
        email.Body = "<div style=""font-family:Arial"">Messaggio prima di includere l'immagine:<br /><br /><img src=""@@IMAGE@@"" alt=""""><br /><br /> Descrizione dell'immagine sopra inserita.</div>"


        ' Creare il INLINE 
        Dim attachmentPath As String = PERCORSO_LOGO

        ' generate the contentID string using the datetime
        Dim contentID As String = Path.GetFileName(attachmentPath).Replace(".", "")

        Dim inline As New Attachment(attachmentPath)
        inline.ContentDisposition.Inline = True
        inline.ContentDisposition.DispositionType = DispositionTypeNames.Inline
        inline.ContentId = contentID
        inline.ContentType.MediaType = "image/gif"
        ' "image/png" ; "image/jpg"
        inline.ContentType.Name = Path.GetFileName(attachmentPath)
        email.Attachments.Add(inline)

        ' replace the tag with the correct content ID
        email.Body = email.Body.Replace("@@IMAGE@@", "cid:" & contentID)

        'Invio email con GMAIL SMTP

        Dim credenziali As New System.Net.NetworkCredential(USERNAME.ToString(), PASSWORD.ToString())
        Dim smtpClient As New SmtpClient("smtp.gmail.com", 587)
        'Se è necessario ed è supportata la cifratura SSL
        smtpClient.EnableSsl = True
        smtpClient.Credentials = credenziali

        Try
            smtpClient.Send(email)
            email.Dispose()
        Catch smtpException As SmtpException
            MessageBox.Show([String].Format("SmtpException : {0}", smtpException.Message))
        Catch ex As Exception
            MessageBox.Show(String.Format("Exception: {0}", ex.Message))
        End Try

    End Sub