knowbility
Accessibility, What NOT to do

Accessible Images

Guidelines

WCAG 2.0

  • Guideline 1.1 Provide text alternatives for all non-text content.

    1.1.1 For non-text content that is used to convey information, text alternatives identify the non-text content and convey the same information. For multimedia, provide a text-alternative that identifies the multimedia.

    1.1.2 For non-text content that is functional, text alternatives serve the same purpose as the non-text content. If text alternatives can not serve the same purpose as the functional non-text content, text alternatives identify the purpose of the functional non-text content

    1.1.3 For non-text content that is intended to create a specific sensory experience, text alternatives at least identify the non-text content with a descriptive label.

    1.1.4 Non-text content that is not functional, is not used to convey information, and does not create a specific sensory experience is implemented such that it can be ignored by assistive technology.

section 508

§508.1194.22(a) A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content).

Goals

  1. Every <img> tag must include the alt attribute. Testing tools will spot these errors.
  2. All image links/buttons/hotspots must have non-empty alt attributes. Testing tools catch most of these errors.
  3. If the image conveys "important" information it must have a non-empty alt attribute. Testing tools cannot catch these errors.
  4. Don't hide information using the background attribute.

Resources

 

 

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