Ensure image alternative is not repeated as text

The image-redundant-alt rule checks that alternative text (alt attributes) for images inside links or buttons does not repeat nearby visible text. Redundant alt text can cause screen readers to announce the same information twice, which is unnecessary and potentially confusing.

What is being tested?

This rule ensures that:

• Images inside links or buttons do not have alt text that duplicates adjacent link or button text.
• Image buttons have alt text that clearly describes the button’s action or purpose, not the image file or visual appearance.

Bad example

<p><a href="index.html">
  <img src="images/home-icon.png" alt="Home Page" width="24" height="25">
  Home Page
</a></p>

In this example, the screen reader would announce “Home Page Home Page,” which is redundant. Instead, the image’s alt attribute should be empty.

Good example

<p><a href="index.html">
  <img src="images/home-icon.png" alt="" width="24" height="25">
  Home Page
</a></p>

Image button example

<input type="image" src="submit.png" name="submit" height="36" width="113" alt="Submit">
Submit

For image buttons, the alt text serves as the button’s label and must describe the button’s action, not the image.

Why it matters

Redundant alternative text can confuse screen reader users by causing repeated announcements. Alt text should provide useful, non-duplicated information that communicates the image’s purpose or action. For image buttons, clear and concise alt text helps blind users understand what the button does.

Best practices

• Do not duplicate adjacent link or button text in the image’s alt attribute.
• Use empty alt="" when an image is purely decorative or when the adjacent text already provides context.
• For image buttons, make the alt describe the action (e.g., “Submit” or “Search”), not the image appearance or file name.
• Avoid non-useful alt text like “chart,” “image,” “diagram,” or file names.