Images

Images not only provide visual appeal to our pages, they also convey important information. The old adage, that a picture tells a thousand words, can be very true! The problem occurs when we add an image that provides content to our students, but fail to provide an adequate text alternative for students who are visually impaired. The alternative text--called alt text for short--feature allows you to provide a description of the image. 

There are times when images not only provide information, they also serve a function, such as button or links to additional resources. In this case, the alt text should clarify the function.

There are scenarios where descriptive alt text is not required--some times a cigar is just a cigar, and sometimes an image is just there for visual appeal. It's purely decorative. In this case, alt text is not necessary, as the image has no value to a student using assistive technology. Many images, however, have a pedagogical purpose, and, therefore, require a description explaining the information the image conveys. 

Common Mistakes

The common mistakes with alternative text can be summed up in a very short list:

  • A purely decorative image does not have a "null" alt text.
  • The file name, including .png or .jpg is used instead of alt text.
  • No alt text is provided for an image that has pedagogical value.
  • Not enough alt text is provided to explain content rich images, such as graphs and charts.
  • The actual text of the alt text contains redundant information or words. 

How to Format Alt Text

General Rules For All Alt Text

The accessibility experts at WebAim provide the following guidelines. The alt text should:

  • Be equivalent in presenting the same content in and function of the image.
  • Be succinct. This means the correct content (if there is content) and function (if there is a function) of the image should be presented as concisely as is appropriate. Typically no more than 10 words.
  • NOT use the phrases "image of" or "graphic of" to describe the image. The screen reader will announce the image. If the medium of the image is an important aspect (such as a photograph or oil painting), then the medium should be included.
  • NOT contain file extensions such as .jpg or .png

Before you select "Next" please read through all the "How to Format Alt Text" tabs above. 

Additional Resources