Alternative text describes the content of images, graphs and charts. It should be added to every image in your Canvas course that conveys meaning.
Images, charts, and graphs are key means of providing information in Canvas courses. However, people with visual impairments cannot see that information. Alternative text provides a text description of visual depictions that can be read aloud, offering visually impaired individuals and sighted individual a similar experience. Also, if a sighted user has a limited internet connection and images cannot or are slow to load, the alternative text will provide the user with the information the image portrays.
Any image, chart, or graph that conveys information must have an alternative text description. If the image is purely decorative and does not convey any information, it can be marked as a decorative image. Here's how to access the alternative text options in Canvas. When writing alt text, your description should:
- Be meaningful and concise.
- Provide the necessary information that the image is trying to portray, which will depend on the context of the image.
Example of Alt Text with Various Contexts
Alt text with no context:
Alt text in an article about orientation:
New students touring campus near Silverman Hall
Alt text in an article about academic accomplishments:
Richard and Barbara Silverman Hall for Molecular Therapeutics and Diagnostics
Charts and Graphs
- Use the alt text option to provide a description of the key information from a chart or graph.
- If the entire chart or graph needs to be described, consider including the description in the body of the text or writing a separate document and linking to it in the body of the text.
Thing to Avoid
- Avoid including the terms “picture of” or “image of” in the alt text. Screen readers will automatically identify the object as an image for the user.
- Avoid describing only the surface features in the image.
- Avoid providing more detail than necessary. Only explain what you want the image to convey.
- Avoid using the file name itself (ex. classroom.jpeg) as the alt text.
- Avoid using the same alt text for similar images depicting different things.
- Avoid duplicating a description in alt text that already exists in the body of the text. In this case, identifying the image and pointing to the text description is appropriate alt text.
- Avoid writing alt text longer than 125 characters. Anything more that is needed should be included in the body text.
When adding new images, charts, or graphics to your Canvas page, use the image button above the Rich Content Editor. This will bring up a box to upload an image. Once the image is uploaded, directly below the image is a box to add alternative text or to indicate that the image is decorative. Adding alt text in the development phase will make your page more accessible and result in less remediation work in the future.