Using Alt Text for Its Intended Purpose

An alternative-text feature allows blind readers and those with low vision to hear descriptions of what they can’t see online. The point is to improve digital accessibility. NASA uses the feature with an “ALT” link that opens an “Image Description.”

This Harvard Digital Accessibility guide provides tips for writing good alt text:

• Add alt text all non-decorative images.

• Keep it short and descriptive, like a tweet.

• Don’t include “image of” or “photo of.”

• Leave alt text blank if the image is purely decorative

• It's not necessary to add text in the Title field.

I would amend this list by suggesting that writers limit the number of “purely decorative” images in favor of meaningful ones.

Twitter users and others are frustrated by alt text that doesn’t meet these criteria and, worse, is used for purposes other than increasing accessibility. Unfortunately, people are using this feature for source information, additional captions, or jokes. Of course, this does nothing to help users who need assistance navigating web content—the intended purpose of alt text.