Images must have alternate text

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Rule Description

All images must have alternate text to convey their purpose and meaning to screen reader users.

The Algorithm, in Simple Terms

Ensures that every <img> element has alternative text, role="presentation" or role="none" (ARIA 1.1).

Why this is Important

Screen readers have no way of translating an image into words that gets read to the user, even if the image only consists of text. As a result, it's necessary for images to have short, descriptive alt text so screen reader users clearly understand the image's contents and purpose.

How to Fix the Problem

Ensure all informative <img> elements have short, descriptive alternate text and all decorative <img> elements have empty alt attributes (e.g. alt="".

Compliance Data & User Impact

User Impact: Critical
Disabilities Affected:
  • Blindness
  • Deafblindness
Issue Type:
  • WCAG 2.0 (A): MUST
  • Section 508: MUST
  • WCAG 2.1 (A): MUST
WCAG Success Criteria:
  • 1.1.1 Non-text Content
Section 508 Guidelines:
  • 1194.22 (a) Text equivalent for non-text elements

Related Deque University Course Pages

Other Related Resources

Additional Information

Relevant Technologies:
  • HTML 4
  • HTML5
Test Reliability: Automated testing is possible, with high accuracy
Rule ID: image-alt