Web Development
Web Developer Guidelines
Visual Design Recommendations

Checkpoint 5.9 - Core

An image that conveys no information has a null alt attribute

WCAG 1.0 Priority 1

WCAG Guideline 1. Provide equivalent alternatives to auditory and visual content.

In some instances images can be used to enhance the aesthetics of a page. These ornamental images should be inserted into the stylesheet and not into the HTML of the page. However where the image has to be in the HTML, the alt attribute still needs to be provided, but it should be empty.

When a screen reader encounters an image with an empty alt attribute, it ignores the image completely, which is acceptable if the image doesn't contain any information. On the other hand, without a valid alt attribute screen readers would read, and a text-only browser like Lynx would display, the image file name and the path. This might render the web page inaccessible to users of screen readers and text-only browsers.

Requirement

If the image does not convey any information, provide an empty alt attribute.

Example

<img src="/images/photo.jpg" alt="" width="35" height="39" />

Checking Tool

  • Analyse images and their alt attributes to ensure that purely decorative images have empty alt attributes.
  • Internet Explorer - AIS Toolbar: Images > Toggle Image > Alt
    This will turn all images off replacing them with the values off ALT tags.
  • Firefox - Web Developer's Toolbar: Images > Display Alt Attributes

Information Source

The original source of this information is located on the W3C web site  (www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent)

 

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