Alternative Text for Images
Who Benefits?
People with Disabilities Related to Vision
A screen reader cannot understand the contents of an image without an alternative text (alt text) attached.
Alt text provides a way to make the contents of the image accessible to a person with visual impairments, including color blindness.
Alternative text descriptions of images (ALT text) allows screen reader users to benefit from the information being conveyed by an image.
Adding alternative text to an image is easy to do and likely less time consuming than removing the images and reformatting your document.
People with slow internet Connections
Allows people with slow internet connections or other technical limitations to access the image content in words when the image is not visible.
Users who may need help understanding visual content
Alt text helps users who have difficulty understanding visual content by telling them important elements in words instead of images (non-visual learners).
How To Do This
Different images will require different approaches.
Simple Images:
- If the image is purely decorative and adds no value to the content, then simply write “decorative.” Some applications give you the option to check a box if the image is decorative.
- If the image is not decorate, then a simple description, 100 words or less that explains the contents of the image is all that is needed.
- If the image provides a visual illustration of a process, diagram, or model that supplements the existing text explanation, then something as simple as “illustration of the [process],”
- Consider what is important about an image to convey to the reader.
Complex Images
Some images, such as graphs, charts or informative illustrations require fairly lengthy explanations to make them accessible. When this is the case, there are a few options:
- Provide a brief alt text description of the image and a longer description within the text of the document. This may be helpful for others as well since some people have difficulty understanding charts and graphs.
- Provide a brief alt text description of the image and create a section at the end of the document for long descriptions.
- Provide a brief alt text description of the image and create a separate document with a long description of the image.
- If the image is of a table, convert it to an actual table. It is much more accessible as a table than an image. See the section on Tables for more information on how to do this.
Don't Do This
DO NOT use the words "image of" or "graphic of" because the screen reader already tells the user it is an image or graphic.
DO NOT use images of tables if at all possible. Convert the graphic to an actual table that the screen reader can read.
Resources:
Adding Alt Text to a Word document
Everything you wanted to know about alt text in Microsoft Office documents