Image Alternatives

The first WAI Guideline instructs Web designers to "provide equivalent alternatives to auditory and visual content." This is perhaps the most basic of the fourteen Guidelines, but it is also the most important. The Web in general, and art-related sites in particular, rely heavily upon images to convey information; audio content is also found on many museum Web sites. But people with visual or hearing impairments may be unable to perceive multimedia features such as images and sounds. By providing equivalent alternatives, however, all Web visitors will be able to experience to some degree the content conveyed by these visual and aural elements. Equivalent alternatives frequently take the form of text, which is the most broadly accessible type of content available on the Web. It is important to note that Guideline 1 does not prohibit the use of multimedia such as images and sounds, but rather suggests how to convey that content in different ways so all users can understand its meaning.

Images are certainly the most common type of media found on the Web, so equivalent alternatives must be consistently provided for the benefit of people who are unable to see them. Every image within Access Art is accompanied by two kinds of equivalent alternatives: the first indicates what the image is, and the second describes what it looks like. This practice is applied to all images on the site, whether they are simple graphics such as logos and icons, or complex pictures of art objects. This page describes how Access Art implements the first technique, image alternatives, while the Image Descriptions page addresses the second.

Image alternatives can be easily provided by taking advantage of a feature of Hypertext Markup Language (HTML), the language that controls the format and function of Web pages. To place an image onto a Web page, a designer inserts a particular HTML element into the document; this element is referred to as an "image” tag and it appears as a three-letter abbreviation between brackets.

  <img>

In addition to this term, another statement (called an attribute) must be placed into the brackets. This attribute indicates the filename or "source" of the image; it too is abbreviated.

  <img src = "filename">

While no further information is required to produce a visible image on the page, there are several optional attributes that may be used to control properties of the image, such as its size and its relation to surrounding screen elements. One such optional attribute can be added to provide a text alternative that briefly indicates what the image is. The “alternative” attribute is also abbreviated, and is used alongside the source attribute within the same image tag.

  <img src = "filename" alt = "description">

Text alternatives are not captions that appear alongside the image, and in most cases they will not even be visible on the page. However, there are several ways in which they benefit visitors, particularly those with visual impairments. Web visitors who are blind typically use specialized computer software and hardware that reads pages aloud to them. If a Web page includes text alternatives, these phrases will also be vocalized, informing users about the images found on the page. Without text alternatives, users will not know what the images are or why they are there.

Every image on Access Art is accompanied by a text alternative that is generally no more than a few words in length. Because of their brevity, text alternatives are not used to describe the appearance of images, but simply to identify what they are. For example, the following line of HTML code could be used to identify the Access Art logo:

  <img src = "logo.gif" alt = "Access Art">

For pictures of artwork, the title of the piece is provided as the image alternative.

  <img src = "12.jpg" alt = "RABBIT IN THE MOON MENUKI">

Japanese Edo period (1615 - 1868)
RABBIT IN THE MOON MENUKI, 18th - 19th century
Gold
Height 1/4 inch Width 1 7/8 inches
Gift of Mrs. Virginia W. Kettering, 1974.52.29