Image-ine That: Writing good “alt text” for images on the web

As the Libraries prepare to move into our new Drupal-powered website, we are also preparing to think differently about how we use images. The new site, in keeping with current trends on the Web, will be somewhat more image-heavy than the old one. Working with our colleagues in the Advancement Office, we plan to offer guidance to help content creators find and select images that will convey the tone and “brand” our website needs to communicate while being both pleasing and informative for people using the site.

Once you’ve chosen an image, you will want to consider providing “alt text” – a text alternative to the image, stored in a metadata field along with the image (any content management system, including our new Drupal system, provides for this to be entered when the image is uploaded or edited). This text is used by people who use a screen reader to “see” the site for them, and may also be useful for people on a low-bandwidth connection (perhaps in a rural area or a developing country) or even people who are browsing via mobile device who may have images turned off to save on data charges or speed up the time it takes to load web pages. Like most design techniques that can be implemented to improve web accessibility, adding alt text benefits more users than just those with disabilities!

At first glance it may seem like a simple thing to input a few words describing your image. But like all web content (and yes, alt text is content!), it’s worth taking a moment to think about how to create this text so that it will be as useful as possible. Think first about what you are trying to convey with your image. What information does a sighted person gain from it? What is the image’s purpose? As WebAIM explains in an excellent article about appropriate use of alt text, context is super-important here. What purpose does the image serve in the context of the rest of your page? A picture of cute kittens may be simply decorative, or it may be used to describe the stages of kitten development. In the former case, you may not need to provide alt text since the image is not contributing to the intellectual content of the page. In the latter, your alt text may read something like “Two-week-old kittens whose ears have not quite begun to stand up.”

Three kittens illustrate the point about using kitten pictures.
In this case, a kitten is just a kitten.
Credit: Mathias Erhart/flickr

There are some special cases when you may change your alt text depending on context, and 4 Syllables has outlined several of them. For example, what if your image has a caption? And what do you do differently if your image is actually a map?

4 Syllables has also created a great decision tree for use in developing alt text. Note that in some cases they recommend using blank alt text (alt=””), but at IU, we do expect alt text for ALL images.

decision tree - see 4 Syllables article linked above for full description
credit: 4 Syllables

Like all things related to user experience, a little thoughtfulness goes a long way when creating alt text. Take a moment to consider who’s using your content and what they’re trying to gain from it, and the effort will pay off in web content that is more accessible, more usable, more useful – in short, better for everyone!

Author- Anne Haines

Web Content Specialist in the Discovery & User Experience Department, IU Libraries. I've spoken at events including edUi, Confab Central, Confab Higher Ed, IOLUG, ILF, the IU Libraries' Digital Library Brown Bag series, and the Libraries' In-House Institute. You can find me hanging out at the intersection of content strategy and librarianship, singing a doo-wop song under the streetlight. Follow me on Twitter: @annehaines