Alternative Text: Understanding the issues
Understand the purpose of alternative text and its associated pain points.
Time estimate: 3 to 5 mins
Lesson contents:
Part 1 | Alternative Text: Understanding the issues
- Types of image descriptions
- What is alternative text
- Missing alt text is like gaps in a storybook
- How does missing alternative text impact assistive technology users?
- How does missing alternative text impact people without disabilities?
- How common is missing alt text?
- How does alternative text matter to you or someone you know?
- Takeaways
This training helps:
Anyone who creates and manages images on documents or websites.
- Content writers
- Marketers
- Designers
- … and more
Types of image descriptions
Image descriptions explain visual content and meaning. This benefits everyone.
Types of image descriptions:
Alternative text: Short descriptions used by screen reader users. It’s hidden from anyone not using a screen reader, braille device, or similar technologies.
Captions: Visible explanations next to an image to add more context.
Long descriptions: Visible and detailed explanations of complex images like infographics. They provide more information for all users.
What is alternative text?
Alternative text otherwise known as alt text and text alternative provides a brief description of the image. The text information can be rendered visually, auditorily, tactilely, or any combination.
People who use screen readers, refreshable Braille displays, and other assistive technology rely on the description. Without alt text, people who can’t view the image will not have access to important information.
Missing alt text is like gaps in a storybook
Imagine reading an exciting comic book, only to find key pages missing!
You can guess what happened, but you’re missing important details. You might have to search for another copy or look it up.
Without all the pages, you can’t enjoy and understand the story the same way everyone else can.
The experience of missing information in a story is what it’s like when there’s missing alt text for people using screen readers or other assistive devices.
How does missing alternative text affect assistive technology users?
Screen readers and other assistive technologies read the alt text of an image out loud or provide it tactilely on a Braille device. This helps users understand the meaning of the image in context.
If there is no alt text, technology may try to fill the gap. In some cases, assistive technology reads the image’s file name. In other cases, an application or platform may automatically add alt text. This can provide wrong information about the image.
Check out the audio clips for examples of what a screen reader says when alt text is included and when it’s missing.
Image with alt text
In this example, the screen reader announces text from the web page. Then, it reads the alt text of an image.
“Check out our new line of dog harnesses that will have your pet going out in style! A Labrador Retriever sits in the sun wearing a bedazzled harness, image.”
Image without alt text
In this example, the screen reader announces the same text from the web page. Since this image doesn’t have an alt text, it announces the file name.
“Check out our new line of dog harnesses that will have your pet going out in style! IMG underscore six-thousand-five-hundred-forty-six PNG, Image.”
How does missing alternative text impact people without disabilities?
Besides helping people with disabilities, alt text can help other users, too. If you have a bad internet connection or your email system blocks images for higher security, alt text will appear instead of the image.
For example, if you work for Company ABC and receive an email from someone outside that company, the security system prevents the image from showing.
How alt text may show up in your email
Logo with alt text:
Since the image came with alt text, sighted people will see a broken image icon with the alt text written: “Company ABC logo.”
With alt text, you can still understand what images were meant to convey, without sacrificing your security.
Logo without alt text:
Since the image did not have alt text, sighted users may see a blank rectangle, broken image icon, or its file name like “image4281”.
Without alt text, it’s impossible to know if you’re missing out on valuable information.
How common is this missing alt text problem?
55.5%
Missing alternative text errors affected 55.5% of out of 1 million tested home pages in the (2025 WebAIM Study).
This shows just how common this painful experience is for everyone, especially for people with vision disabilities. Luckily, we can improve this with tips in Part 2 of Alternative Text training.
How does alternative text matter to you or someone you know?
Please reflect on which scenarios apply to you or someone you know:
- I/they use a screen reader to understand information in images
- Some images in my/their email doesn’t show up because of security
- I/they travel or hike and don’t have a good internet connection to load images
- I/they live in an area with inconsistent internet connection
- I/they use a search engine that matches results using alt text (e.g. Google, SharePoint, etc.)
- Other
- I/they don’t need alt text
Takeaways
Alternative text can help people who use assistive technology understand visual information and make sure everyone can access all parts of a story.
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