Alternative (alt) Text

What is "alt text"?

Alt text (alternative text) is a short, descriptive text that explains what an image shows. It helps users who cannot see the image - whether due to blindness, low vision, or slow internet connections. Alt text is read aloud by screen readers and appears if images fail to load.

All visual elements such as photos, icons, and diagrams must have an alternative text (‘alt text’) that briefly explains the purpose of the image, or object summary, as required.

Good alt text conveys the purpose and content of images, ensuring everyone can access the information. It also helps with search engine optimization and usability.

Image Types

Informative images

Informative images are essential for understanding a document's content. They provide information that cannot be conveyed through text alone. These images should always have descriptive alt text that explains their purpose and content. Informative images are not purely decorative; they add value to the document by conveying important information.Examples include:

• Charts, graphs, and data visualizations
• Diagrams and illustrations that explain concepts
• Screenshots showing software interfaces or processes
• Maps and floor plans
• Product images in catalogs

Decorative images

If an image adds no information, mark it decorative so it’s skipped by screen readers. In authoring tools, use “Mark as decorative.” These are images used purely for visual appeal or design purposes that don't convey essential information. Unlike informative images, decorative images should be ignored by screen readers to avoid unnecessary interruptions.

Logos

Logos that serve a function (brand identification) typically should not be marked decorative in formal templates. Provide appropriate alt text describing their purpose.

Writing good alt text

1. Describe essential information or function, in under ~140 characters (with spaces) in English or 170 characters (with spaces) in French.
2. Use plain language
3. For charts and graphs, summarize key trends or data points.
4. Write "Screen Capture" or "Screenshots" as required

Referential Alt Text: If the surrounding text or captions already describe the image’s content, the alt text can be brief and refer back to that description.

Avoid

• Writing “Image of …” — screen readers already announce images.
• Repeated or redundant information that can already be inferred from context

How to add alt text

Follow these steps to add alt text to images in your documents:

1. Right-click the text or object to bring up the contextual menu
2. Select “View Alt Text…”
3. Write a description of the image in the Alt Text pane.
4. In the Alt Text pane that appears on the right:
   • Type a brief, clear description in the text box
   • Keep it under 140 characters (with spaces)
   • For tables/charts/graphs, summarize the key data or trend
   • Focus on the image object's purpose or key information
5. If the image is purely decorative, check Mark as decorative
6. Click outside the pane or press Enter to save