Is alt text required for an image if the information is present elsewhere on the page?

1. Do all images need alt text?
2. When should an image have alt text?
3. Is it necessary for an image to use an alt tag to be accessible?
4. When not to use alt text?

Do all images need alt text?

The short answer to this question – and the answer many people don't expect – is that not all images need alt text. In the accessibility world, we differentiate between images that are decorative and images that are informative. Decorative images usually don't need alt text.

When should an image have alt text?

Alternative (Alt) Text is meant to convey the “why” of the image as it relates to the content of a document or webpage. It is read aloud to users by screen reader software, and it is indexed by search engines. It also displays on the page if the image fails to load, as in this example of a missing image.

Is it necessary for an image to use an alt tag to be accessible?

If no alt attribute is present, the screen reader will read the file name for the image instead, which can be a major distraction to those using screen-reading technology.

When not to use alt text?

3. Including alt text for decorative images or items. Decorative items such as dividers or design items that don't provide additional context or content don't need alt text. They don't add to the information a user needs and they make little sense, or are unnecessary, when read with a screen reader.