Designing and building websites that are accessible to visually impaired users and comply with the Americans with Disabilities Act of 1990 (ADA) can present a significant challenge for web development professionals. There are numerous visual impairments—partial blindness, low vision, tunnel vision, color blindness, and so on—with different underlying causes and effects on the vision of those afflicted. While that varied nature can make any design element problematic for some visually impaired individuals, images are the closest thing you’ll find to a universally troublesome element.
A significant number of visually impaired users employ adaptive technologies like screen readers to help them interpret what’s being displayed on their monitors—and the cues are often inserted programmatically by designers. That means your first decision when dealing with images is whether you ought to make them visible to/recognizable by adaptive tech. In cases where the image is purely decorative, it can be rendered “invisible” to adaptive tech in several ways. The simplest are a null alternative text value (<img alt=””>) or using ARIA (<img role=”none”>, for example). Nothing else needs to be done.
If the image conveys relevant information, though, adaptive technologies need to be able to relate that information to users. The simplest method, once again, is to use an alternative text value. Instead of an intentional null, you can enter text that either describes the subject of the image (<img alt=”the distinct marking on black widow spiders is red and shaped like an hour-glass”>) or the feeling it’s meant to convey (<img alt=”picture of lightning to describe a moment of inspiration”) to the user. Screen readers and other adaptive technologies will use these programmatic cues to help the user get a sense of what’s being displayed and the information they’re meant to glean from it.
Making images—an inherently visual medium—accessible to those with visual impairments can be a challenging task. But we live in an age where you, as design and development professionals, can help people see with a few lines of code. The payoff far exceeds the challenge.