Alternative text

Describe the image

A good alt text description considers the context of the content as a whole and is respectful of its subjects.

Consider the context

Alt text is too short to describe every visual detail of an image. Instead, try to describe the information that the image adds to the content.

Consider the following image:

Currently, the alt text on this picture is neutral.

alt="Person in hi-vis snowsuit applies salt to cleared staircase after snowfall as multiple individuals in winter clothing walk by."

If the article using this image is about a recent bout of inclement weather on campus, the alt text might focus on the signifiers of harsh weather.

alt="Facilities staffer salts snowy campus steps as bundled-up students brave the blizzard."

In an article about UW–‍Madison’s efforts to reduce the use of salt due to the environmental impact of runoff into the lakes, the alt text might highlight different aspects of this image.

alt="Facilities staffer sprinkles salt and sand on shoveled stairs next to closed stairs slicked with snow and ice."

Describing people

The way someone’s physical appearance or identity is described is very personal, and the level of detail each individual is comfortable sharing varies greatly. When deciding what level of detail to use when describing a person in an image, consider the following questions:

• Does the image introduce a specific person?
• Is the purpose of the image to bring attention to a particular group or event?
• Are the subjects or events of the image directly related to the content, or does the image represent a general topic or message?

When describing images of specific people, the best practice is to include descriptions provided by the subjects when possible. This approach is appropriate for scenarios like interviews or staff pages on websites.

Sometimes the subject of an image is not available to give a self-description, like when covering general news or historical events. It’s okay to find descriptions in related documents by or about the subject. When straying from self-description, be mindful of the descriptive language preferred and used by the subject or their community and culture.

If personal attributes were not self-described and are not vital for the message being conveyed through the image, use non-descriptive language and focus on concrete details from the image, for example, “Headshot of Dr. Alison,” or, “Three students cheering on the team in red and white Badger gear.”

AI for alt text

A common exercise used for writing alt text is to try describing the image as if you were reading an article to someone on the phone. A modern twist on this method is to figure out how you would prompt an AI image generator to recreate the same image, and include that information in the alt text.

Many generative AI tools can process images and create descriptions, including UW–‍Madison’s enterprise generative AI tools. When writing prompts for AI tools to generate alt text, include:

• A 150 character limit
• The tone and topic of the surrounding content

Here is an example of an image uploaded to Copilot and a couple of different prompts used to generate alt text.

Write alternative text for this image for an article about campus architecture, limited to 150 characters

alt="Modern campus building with concrete facade and large windows, lit at dusk, with students nearby and a bus passing in the foreground."

Write alternative text for this image for an article about late night library hours during finals, limited to 150 characters

alt="Library glows at dusk as students pass by with a bus rolling past the busy campus entrance."

The most common barrier created by AI-generated image descriptions is inaccurate or lengthy alt text. When using AI-generated descriptions, you must edit for accuracy to ensure truly equal access to the content.