Alt text

Alt text should describe what is in the photo so that screen readers and search engines can describe what the photo represents.

Image

Good Alt text for this image would be:

Cat with cone on its head after surgery

How to add Alt text to an image

To add alternative text in a content management system like Drupal or WordPress there is usually a dialog box with an Alternative text field that looks similar to the following:

Simple alt text tips:

• Explain why the image is important to you in its context. 
• Never start with "Photo of" or "Image of". That is already announced to the screen reader.
• If the alt text is very long, you can add a period. On some screen readers, it will pause or take a breath, which will make it easier to comprehend.
• Images that are purely decorative do not need alt text, but the alt attribute must still be available to tell the screen reader software that it is intentionally blank.
• When in doubt add alt text.

Alt text tips for complex graphics

Information about complex alt text for graphics can be found in these articles:

• Daisy.org - the Art and Science of Describing Images 
• Diagram Center - Image Description Guidelines
• Color and color contrast in graphics