SMTP Image showing as attachment thumbnail

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1

Hi there,

I have had to use VB.net code to send SMTP with embedded images as I found that using the standard SMTP activity with attachments didn’t work properly (show as attachments), and base64 not supported by some email client.

The email body looks perfectly fine with embedded images using Content ID method and Linked Resources.

However, I get an inconsistent behaviour with how the message previews appear in Gmail. As you can see here, sometimes the thumbnail appears under the Subject. Sometimes it does not. I would like for it not to show any thumbnail/attachment here.

Any ideas what would be causing this? It seemed to change behaviour by simply changing the recipient…

Screenshot_20231026_204323_Gmail
Screenshot_20231026_204323_Gmail1077×718 83.8 KB

Screenshot_20231026_204353_Gmail
Screenshot_20231026_204353_Gmail1080×598 78.5 KB

2

Is it showing the file upon opening the mail even if it doesn’t show any thumbnails

Otherwise If your email’s content is primarily HTML with embedded images using Content ID (CID), Gmail might try to display the embedded images as thumbnails.

Keep your email structure as simple as possible. Avoid complex HTML structures. A plain text email with image attachments (not embedded) may be less likely to display thumbnails.

Test with different email addresses to see how Gmail handles the email in different environments.

Cheers @Jon_G

3

When you click on the email itself, there are no attachments and the images are just embedded in the email body itself, which is exactly what is intended.

It’s only when viewing in the Preview like listed here, it shows the first image as if it’s an attachment. There’s actually 5 images in the whole email. It’s a company branded email outbound to customers so I can’t really use plain text.

4

Well there are certain factors which are influenced by Gmail automatically
But to take it form your side I would recommend to try out these

  1. If ur intention is to share image you can share it as a url or hyperlink instead of image that would avoid this thumbnails

  2. Or you can modify the html code and image header tags. Experiment with different email header tags or metadata. Gmail’s behavior in the Preview may be influenced by how it interprets these tags. Specifically, look into the “Content-Disposition” and “Content-Type” headers for your images.

  3. Try with different file format.
    Check the encoding and format of your embedded images. Using standard image formats like JPEG, PNG, or GIF and ensuring that images are correctly encoded might help.

Hope this clarifies
@Jon_G