Images and other non-text content should include alternative text (alt text) to provide access for users with visual impairments.
- Alt text should be as succinct as possible--no more than a sentence or two.
- Avoid language that conveys emotion--let the user decide how they feel about the content.
- Convey the purpose of the image, rather than just a purely visual description.
- Context is everything! The same image could have different meanings depending on the context.
- If the purpose of the image is to share the details of the photo or artwork, use the alt text to "paint a picture" with words.
- Include any text that is conveying information in the image.
- Do not include redundant information in alt text if the same details are provided in a caption or surrounding text.
- Do not use phrases such as “image of” or “graphic of” unless the purpose of the photo is to show a portrait, painting, etc.
- Decorative images that do not convey meaning should include empty alt text (alt="")
Complex Images
Infographics, charts, screenshots, maps, and other images that convey complex information may need a longer description than what is typically used for alt text.
- In these cases, the full description can be included with accompanying text, or it can be linked on a different page.
- The brief alt text for the image can mention that details are found in the text before or after the image.
Decorative Images
Images that do not convey any significant meaning can have an empty alt attribute.
- Empty or null alt text (alt="") tells a screen reader that it can ignore the image. If the alt attribute is not there at all, a screen reader will announce that there is an image and read out the image file name.
- Some programs give an option to mark an image as decorative. If not, you may need to add a space in the alt text field.
