[FAQ]

I’m a freelance marketer based in Chicago, and I’m building out a new email template for a client. I’m trying to make sure I’m following the absolute best practices for including images.

I know there are different methods, and I’ve heard people talk about CID embedding versus just linking to an image on a server. I’m not totally clear on the difference or which one is the standard for marketing emails today.

My main goals are to make sure the images always display correctly for everyone and that my emails don’t get flagged as spam. What is the most reliable and deliverability-friendly way to get images into an email?

Thanks for the help!

[Jeff Bullas]

An important question for deliverability and performance.

Short Answer: The best and only recommended way to embed an image in a marketing email is to host the image file on a secure server and link to it in the email’s HTML. ‘True’ embedding, where the image data is attached to the email, should be avoided.

This distinction is critical because while both methods can display an image, one is friendly to spam filters and the other is a major red flag.

The standard and correct method for including an image in your email is to first upload that image to a reliable web server, like your website’s media library or a content delivery network. The text in your email’s code then contains a simple image tag that points to the absolute URL of that hosted image. This is known as linking. This method is best practice because it keeps the actual file size of the email itself incredibly small, which is the most important factor for good deliverability and avoiding spam filters.

The other method, known as CID embedding, involves attaching the raw image data directly to the email. This should not be used for marketing emails. It dramatically increases the email’s file size, which can cause your email to be blocked by spam filters or “clipped” by services like Gmail, meaning your subscribers will never see your full message. The risk to your sender reputation and deliverability is not worth it.

For your linked images, always ensure you have optimised the image file to be as small as possible before uploading it, and always include descriptive alt text to ensure your message is understood, even when images are blocked.

Cheers,
Jeff

[Author]

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