c# - Send inline image in email

Question

Having an issue sending an image via email as an embedded image in the body. The image file shows as an attachment which is ok but the inline image portion just shows as a red x.

Here is what I have so far

LinkedResource inline = new LinkedResource(filePath);
inline.ContentId = Guid.NewGuid().ToString();
MailMessage mail = new MailMessage();
Attachment att = new Attachment(filePath);
att.ContentDisposition.Inline = true;
mail.From = from_email;
mail.To.Add(data.email);
mail.Subject = "Client: " + data.client_id + " Has Sent You A Screenshot";
mail.Body = String.Format(
    "<h3>Client: " + data.client_id + " Has Sent You A Screenshot</h3>" +
    @"<img src=""cid:{0}"" />", inline.ContentId);

mail.IsBodyHtml = true;
mail.Attachments.Add(att);

Answer 1

Some minimal c# code to embed an image, can be:

MailMessage mailWithImg = GetMailWithImg();
MySMTPClient.Send(mailWithImg); //* Set up your SMTPClient before!

private MailMessage GetMailWithImg() {
    MailMessage mail = new MailMessage();
    mail.IsBodyHtml = true;
    mail.AlternateViews.Add(GetEmbeddedImage("c:/image.png"));
    mail.From = new MailAddress("yourAddress@yourDomain");
    mail.To.Add("recipient@hisDomain");
    mail.Subject = "yourSubject";
    return mail;
}

private AlternateView GetEmbeddedImage(String filePath) {
    LinkedResource res = new LinkedResource(filePath);
    res.ContentId = Guid.NewGuid().ToString();
    string htmlBody = @"<img src='cid:" + res.ContentId + @"'/>";
    AlternateView alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
    alternateView.LinkedResources.Add(res);
    return alternateView;
}