What is email alt text? Platform notes and checklist

Email alt text

Good alt text does not answer “what pixels are in this image?” in isolation. It answers: what does this image contribute in this email?

Start with the image’s purpose

W3C accessibility guidance separates images into useful categories such as informative, decorative and functional images. That same reasoning works well in email.

Informative image

The image communicates information that the surrounding live text does not already provide. Example product card:

• image: green linen overshirt
• surrounding text: product name and price only
• useful alt: Green linen overshirt, front view

If color or product style is part of why the recipient needs the image, include it. Do not write a long photographic inventory of background objects that do not matter.

Decorative image

The image adds visual atmosphere but no unique meaning. Example: a confetti flourish behind a “20% off” headline that already exists as live text.

Use an empty text alternative (alt="") when the image is truly decorative so screen readers can skip it. Repeating “decorative confetti image” adds noise.

Functional or linked image

The image is the main control for an action or destination. If a product image is linked and there is no adjacent linked text that communicates the destination, the text alternative should describe the function or destination, not merely appearance. If the card also has a linked product name, test how both links are announced together. Label the image link so it makes sense by itself without making the reader hear the same destination twice.

For example, Shop the green linen overshirt can be more useful than Photo of green shirt when the image is effectively the call to action.

Context changes the right answer

The same image can need different alt text in different emails. A photo of a red handbag in a product announcement might need New red leather crossbody bag. In an order confirmation where the product name “Red leather crossbody bag” already appears immediately beside it, repeating the same text through the image may be redundant. Write alt text after looking at the whole content block, not from the asset library before the email is designed.

Alt text is also an image-blocking fallback

Email clients and user settings can prevent images from loading. Support for displaying alt text varies, but useful alt text can preserve meaning in clients that show it.

This is another reason image-only campaigns are fragile. If the sale amount, product name, coupon code and CTA all exist only inside a hero image, alt text has to carry too much meaning and recipients may still lose structure or actions. Keep essential copy and calls to action as live HTML text whenever possible.

What does this page teach beyond a generic glossary definition?

It teaches alt text as a context and purpose decision. In ecommerce email, the same product image can be informative, redundant/decorative, or functional depending on the surrounding text and whether the image is the only link. That model also makes image-blocking fallback much more useful.

Common mistakes

1. Do not use the filename. IMG_8492_final.jpg communicates nothing useful
2. Do not prefix every value with “image of.” Screen readers already expose that it is an image in many contexts. Use the space for the meaning
3. Do not stuff marketing copy into unrelated alt text. Alt text should represent the image’s purpose, not become a hidden second subject line
4. Do not repeat nearby live text unless the repetition is needed to preserve the image’s function. Excess repetition makes screen-reader output tedious
5. Do not omit the `alt` attribute for decorative images. An empty value is deliberate; a missing attribute can lead assistive technology to announce unhelpful file information

Comparison