What are decorative images?
Decorative images are images that are only included for aesthetic reasons.
Examples include visual styling such as borders, corners, and presentational lines. If they're removed, it would not impact on the understanding of the story as they do not convey information or meaning.
Stock library images could also be described as decorative. Journalists often use these types of images to break up text for example. These images may not directly add to the story, but a brief text description must be added as it gives an equitable experience to all audiences.
If you're using a straightforward decorative image (visual borders etc) simply put "" in the alt text field so the screen reader will ignore it. Please do not leave it blank! This will result in the screen reader announcing a generic code label which is meaningless to the user, and thereby detracting from the overall experience.
Examples
Decorative lines (and other visual styling)
This piece about St David has a few different examples of decorative images.
Source: St David: Ten things to know about the patron saint of Wales
Original text description: "line".
Recommended text description: Put in empty quote marks – that's "" – as this will instruct the screen reader to skip it. It doesn't need to be described, because it doesn't add information to the article.
Stock photos
Source: Cost of living: North Wales energy bills highest in the UK
Original text description: "Stock image of a smart meter in a kitchen".
Recommended text description: "A smart meter on a table with a kettle and cup in the background" brings across the content and sentiment of the image and provides screen reader users with an equitable experience.
It will also improve SEO rankings and provide a description to anyone whose image hasn't loaded correctly.