Embed image in email with latest C# Sendgrid 9.28.1-CodePudding

I'm trying to embed an image in an email that's send with Sendgrid C# 9.28.1. But somehow the image is not displayed. There is also not a function anymore that's called EmbedImage. Is there a way to do this?

        var client = new SendGridClient(_settings.ApiKey);
        var myMessage = new SendGridMessage();
        myMessage.AddTo(entity.Email);
        myMessage.From = new EmailAddress(_settings.FromAddress, _settings.FromName);
        myMessage.Subject = $"{_settings.FromName} - Image TEST";
        var body = "<div style=\"width:200px;\"><img src=\"cid::IMAGE01\"/></div>"  
                      @"<p>Test message?</p>";

        var attachment = new SendGrid.Helpers.Mail.Attachment
        {
            ContentId = "IMAGE01",
            Content = entity.Base64ImageString,
            Type = "image/png",
            Filename = "image.png"
        };

        myMessage.AddAttachment(attachment);
        myMessage.HtmlContent = body;

        await client.SendEmailAsync(myMessage);

CodePudding user response：

I was able to replicate your issue. When running your code I see the image attached, but not inlined into the body of the email.

To resolve the issue, I added the Disposition property and set it to "inline".

message.AddAttachment(new Attachment
{
    ContentId = "IMAGE01",
    Content = Convert.ToBase64String(File.ReadAllBytes("image.png")),
    Type = "image/png",
    Filename = "image.png",
    Disposition = "inline" // important!
});

Once I added the property, the image was displayed inline. (I also use a single : instead of two : in the HTML, so cid: instead of cid:: but not sure it matters.

Here's what part of my email source looked like without the Disposition property:

<html>
    <body>
        <img src=3D"cid:IMAGE01"/>
    </body>
</html>
--d0e309773e8692891fcbf3a6dc18894582dea28d62adfe2bd8fd84a96b90
Content-Disposition: attachment; filename="image.png"
Content-Transfer-Encoding: base64
Content-Type: image/png; name="image.png"

Notice how IMAGE01 only appears in the HTML, but not in the attachment.

This is with the Disposition property:

<html>
    <body>
        <img src=3D"cid:IMAGE01"/>
    </body>
</html>
--5bb4b7a345af921dc9094ee0d66495c2a390a8aa6e89c2a41d96f8af8af5
Content-Disposition: inline; filename="image.png"
Content-ID: <IMAGE01>
Content-Transfer-Encoding: base64
Content-Type: image/png; name="image.png"

Notice how there's now a Content-ID: <IMAGE01> parameter.

Having said that, there are also two alternatives, you can use a data URL to embed the base64 data into the HTML, or you can upload the image to the internet and reference it.

You can find the source code here: https://github.com/Swimburger/SendGridImages/blob/main/Program.cs