Writing alternative text for images and graphics
Image is not just an image. To know what alternative text to write, you should be aware of the following differences.
However, one thing applies to all alternative texts: keep it concise and meaningful, and avoid additions like 'The image shows...' or copyright notices."
Purely decorative images
For purely decorative images, leave the “Alternative Text” field empty. In practice, it is often difficult to determine whether an image is purely decorative. An image is considered decorative if you can omit it without affecting the meaning or understanding of the webpage.
The image is a link
If the image is a link, the “Alternate Text” field must contain a statement about the link's destination instead of a description of the image. The alternative text will be read as the link text.
Example: The alternative text for a linked logo should include the company name.
The picture is informative
In most cases, these are informative images. A good alt text should concisely, objectively, and contextually describe the image's content.
CHECKLIST
- Concise:
Write clearly and as briefly as possible (no longer than about 90 characters). - Objective:
Describe factually, without interpretations or opinions. - Context-specific:
Describe the aspects of the image that are important for understanding on the associated page. - Direct:
Start directly with the description. Avoid unnecessary phrases like "The image shows…". - No Duplication:
Do not repeat information from the caption.