Alt text
Why describing images helps make digital communication more accessible.
Alt text (alternative text) is a short written description of an image that communicates its essential content or purpose to people who cannot see it or who use assistive technologies such as screen readers.
Alt text helps make digital information more accessible. It can be added to images in websites, documents, presentations, PDFs, emails, social media posts, and many other digital files.
Rather than describing every visual detail, good alt text communicates what someone needs to understand from the image in the context where it appears.
Alt text helps ensure the meaning behind an image doesn't depend on vision alone.
Editorial illustration representing alt text—written descriptions that help make the meaning behind images available to more people.
Why does alt text matter?
Images often communicate information, tell stories, or reinforce key messages. Without alt text, people using screen readers or other assistive technologies may miss information that others receive at a glance.
For governments, this can affect access to public information and services.
For nonprofits, it can affect whether supporters, volunteers, donors, program participants, and community members can fully engage with reports, educational resources, fundraising campaigns, event announcements, and everyday communications.
For businesses and institutions, accessible communications help more people understand and participate in the work they do.
Adding alt text is one small step toward making digital information available to a wider audience.
If an image communicates something important, that information should be available to everyone.
Where is alt text used?
Alt text is commonly added to:
Photographs
Charts and graphs
Diagrams
Illustrations
Maps
Icons
Infographics
Screenshots
Logos (when they communicate information)
You'll find alt text in websites, Word documents, PowerPoint presentations, PDFs, emails, social media platforms, content management systems, and many other digital publishing tools.
What makes good alt text?
Effective alt text is:
Concise
Specific
Relevant to the surrounding content
Focused on the image's purpose rather than every visual detail
The same image may have different alt text depending on why it is being used.
For example, a photograph of a mayor planting a tree might emphasize the mayor during a news announcement about civic leadership, but focus on the tree-planting activity in an article about environmental initiatives. The goal is to communicate what the image contributes to that particular piece of content.
Good alt text
Can be added to more than websites.
Many document, presentation, and publishing tools allow authors to add alt text, helping make reports, presentations, downloadable files, emails, and social media posts more accessible.
Serves a different purpose than a caption.
Captions are visible to everyone and often provide additional context. Alt text helps people using assistive technologies understand the essential content or purpose of an image.
Benefits many people.
While alt text is an important accessibility practice for people who are blind or have low vision, it can also benefit people using screen readers, those experiencing temporary impairments, and others accessing content in different ways.
Supports clear communication.
If an image contains essential information—such as an address, deadline, emergency instruction, or key finding—that information should also appear in the surrounding text. Alt text makes visual content more accessible, but important information should never exist only within an image.
Works best with human judgment.
Many platforms now generate alt text automatically, but automated descriptions may miss context, overlook what's important, or misunderstand why an image was included. Reviewing and refining AI-generated alt text helps ensure it communicates what readers actually need to know.
In practice
Imagine a nonprofit publishes an annual impact report with a chart showing that volunteer participation increased by 35 percent over the past year.
The report's text already explains the increase, so readers don't have to interpret the chart to understand the key finding. The chart reinforces the information visually.
The chart's alt text might read:
Bar chart showing volunteer participation increasing steadily over the past three years, with a 35 percent increase during the most recent year.
Someone using a screen reader can understand what the chart communicates, while every reader has access to the key takeaway through the report itself.
Why it matters
Whether you're publishing a government update, a nonprofit annual report, a classroom presentation, a fundraising campaign, a community newsletter, or a social media post, every image carries the potential to communicate something meaningful.
Adding alt text helps ensure that meaning remains available regardless of how someone experiences the content.
It's one of many small practices that make communication more accessible, more inclusive, and ultimately more useful. By considering how people with different abilities access information, organizations can reach broader audiences and create experiences that invite more people to participate, understand, and engage.
Our perspective
At Public Servants, we believe accessibility is an essential part of effective communication—not an afterthought.
Whether we're designing a service, writing a report, illustrating a concept, building a product, or publishing online, we strive to create work that more people can access, understand, and use. That includes practices like writing alt text, using plain language, providing captions, and considering the many different ways people experience information.
Accessibility is a continuous practice of learning and improvement. By sharing concepts like alt text through our Civic Glossary, we hope to make accessibility more approachable and help more organizations create communications that invite everyone to participate.
