Alternative or alt text should accompany any visual element such as an icon, photo, graph, etc. to describe the image to a screen reader. This alt text will also help users to identify whether an image is important or what it depicts in cases where the image is slow to load or fails to load. 

Alt text should be concise and clear, generally 1-2 sentences or 125 characters max and should describe the content and function of the image. In the case of complex images, graphs or tables, longer descriptions may be required.

Alt text can be added:
  • close to the image in the document,
  • as a longer description which you can link to (like a glossary for images)
  • by using the alt tag where it is saved with the image.
If adding a caption or short description near the image, use the layout options to include it “In Line with Text” to ensure it is read in the correct order.

Word and other document/text editors generally offer an alt text tool which can auto-generate descriptive text but it’s generally recommended to edit this and write your own.

Avoid unnecessary information like “photo of” and focus on creating a meaningful description.

If a photo is not important, or does not add meaning to the content, mark it as decorative in the alt text tool. This will indicate to the user or a screen reader that the image in not important and can be skipped.  

Screenshot of Microsoft Word alt text box

Finally, consider if your image relies on colour to convey key information or if any of this information would be lost if it was printed in black and white, for instance. This could affect users who are colour blind or who require different contrast levels.