Email Copy
Writing image alt text for an email
Choose useful email image alt text by deciding whether each image informs, decorates or acts as a link.
Email image alt text should convey the image's purpose in that message. Describe information a reader would otherwise miss; use empty alt text for a decorative image already explained by nearby text. Do not repeat the filename, stuff keywords into the description or try to narrate every visible detail.
Decide what the image contributes
Before writing alt text, read the paragraph around the image. If it already says “Your order will arrive on Thursday”, a decorative truck illustration does not need to announce “Blue truck delivering an order”. Empty alt text keeps it out of the spoken reading.
W3C's image tutorials distinguish decorative, informative and functional images, and give different guidance for the alt text used for each.
If the image is a chart, product comparison or event notice, identify the information needed for the decision. A useful alternative to a chart might state its main result in text next to it, while the alt text briefly identifies the chart. Complex detail may need a text summary in the body rather than an overlong alt attribute.
| Image in the email | Better treatment |
|---|---|
| Decorative border or stock photo | Empty alt text |
| Product photo beside a clear product name | Brief identifying alt text if the appearance helps the choice; otherwise avoid repeating the adjacent name |
| Banner with the only mention of a deadline | Put the deadline in body text; use alt text to describe the banner's role |
| Image used as a link | Name the destination or action, not just the picture |
These are editorial examples, not rigid labels. The surrounding copy determines whether an image adds information.
Write for the action, not the artwork
Suppose a graphic button says “View your itinerary”. Its alternative text should preserve that action if the button is implemented as an image. “Purple rounded rectangle with white lettering” describes appearance while withholding the purpose.
W3C's link-purpose guidance favours text that lets people decide where a link will take them, even when they encounter it apart from its surrounding paragraph.
For a promotional banner, avoid copying a long marketing sentence into alt text if the same sentence is already in the body. Redundancy can make the email tedious when read aloud. If the banner carries the only explanation of an offer, move the explanation into normal text. Alt text is a fallback for the image, not a substitute for a readable message.
Check the result in context
Turn images off in a test email and read it from the top. Are the remaining lines coherent? Does any linked image have a useful name?
Then review the message with a screen reader or inspect the accessible names in a suitable test environment. The alt text should fit the surrounding sentence and not repeat it word for word without reason.
Also check what the email client actually displays when images are blocked. Some clients show alt text differently or truncate it, so the message's essential facts should live in body copy. Treat alt text as one part of the email's content design, with the same editorial review as headings and button labels.
