Follow these best practices to write good alternative text descriptions for your images:
- Describe the image based on the page context. Convey the full meaning of the image.
- Avoid saying "image of" or "picture of". Screen readers automatically announce images as images.
- Be concise.
- Write narratives for complex images like infographics. Put this narrative on the page immediately following the infographic. Include an anchor link at the top of the page to view the text alternative. See an example of an infographic with a text alternative.
- Avoid images of text. If you can't avoid it, copy the text into the alternative description.
- Say something new. Don't repeat alternative descriptions on the same page. Don't repeat what is already said on the page.
- Identify images that don't represent relevant content as decorative.
What is a decorative image?
An image is decorative when it doesn't add to the information on the page. For example, art work used to separate topics or a photo of someone on the phone when discussing communication skills.
They are valuable in their visual appeal but may not need to be read by screen readers.
Why are alternative image descriptions important?
There are many reasons to use alternative descriptions with your images.
- Alternative descriptions, or text, are in the WCAG 2.1 guidelines
- Students can search for an image
- Students with visual impairments have difficulty perceiving images
- Student with a poor network connection may have difficulty perceiving images
- Screen readers can't read images
- Some students learn better from descriptions than images
- Text scales better than most images when the screen or page is enlarged