Testing for IMG markup using the WAVE Web Accessibility Evaluator

Overview

WAVE is a free web accessibility evaluation tool provided by WebAIM. It is used to aid humans in the web accessibility evaluation process. Rather than providing a complex technical report, WAVE shows the original web page with embedded icons and indicators that reveal the accessibility of that page.

Strengths

  • Provides a visualization of the accessibility of a web page through the use of inline icons

Weakness

  • Requires manual inspection
  • Does not provide a listing of errors
  • Sometimes symbols are omitted on the page

Step 1: Enter the URL of the Page to Evaluate

Procedure

  1. Enter the URL of the page to be tested with the WAVE tool.
  2. Click “WAVE this page!” button.

Screenshot

Screen shot of  Enter the URL of the Page to Evaluate

Step 2: Identify Icons Associated with alt text information and inspect images

Procedure

  1. Identify icons used to identify the alt text:
    * Alt text present
    * Alt text link
    * Image input alternative text
    * Null or empty alternative text
    * Null or empty alternative text on spacer
    * No alt text
    * No alt text for linked image
    * Image input missing alternative text
    * Very long alternative text
  2. Use the tool tips to display the image meaning or click on the image key link at the top of the WAVE page.
  3. Use the image icons to verify that every image element has an alt attribute. (Noninformational images should have null or empty values.)
  4. Verify that every informative image element has meaningful alt text containing 7 to 90 characters. Alt text will be displayed after the image and the alt text icon. The “very long alt text” icon will flag alt text longer than 100 characters.
  5. Verify that the alt attribute does not include the file name of the image.
  6. Verify that the alt attribute does not contain information that is redundant with the img element. For example, avoid using words like “image”, “picture”, “graphic”, “photo” and “photograph”.

Screenshot

Screen shot of Identify Icons Associated with alt text information and inspect images

Rules Evaluated with this Technique

Rules evaluated with WAVE Web Accessibility Evaluation Tool
Test
Type
Description
Manual

Every img element must have alt attribute.

Manual

Descriptions should be meaningful and contain at least 7 and less than 90 characters.

Manual

The alt attribute content should not include file name of the image.

Manual

The alt attribute content should not include information that is redundant with the img element.