Alt Text Made Simple
A Guide to Creating More Accessible Digital Communications
Learning to write effective alt text is one small accessibility step that makes a big difference. The good news? It's easier than you think.
What is Alt Text?
Alternative (alt) text is a brief description added behind an image that helps people using screen readers and other assistive technology understand its purpose and meaning. Rather than describing everything in the image, effective alt text focuses on why the image is there and how it supports the surrounding content.
Think of alt text as answering the question: "What would someone miss if they couldn't see this image?"
Alt Text Isn't the Same as a Caption
Alt text and captions serve different purposes. Depending on the image and context, you may use one or both.
- Alt Text
- Hidden from most users and read by screen readers
- Explains the purpose or meaning of the image
- Caption
- Visible to everyone
- Adds extra context, details, or photo credit
Why It Matters
Alt text helps:
- People using screen readers and other assistive technology
- People with visual impairments
- Users when images fail to load or internet connections are slow
- Search engines better understand your content, which can support SEO
5 Tips for Writing Alt Text for Images
1. Keep it brief.
Most alt text should be one or two sentences. Write in complete sentences and end with a period.
2. Describe the purpose, not every detail.
Focus on the information readers need, not every object, color, or background detail in the image.
3. Consider the context.
The same image may need different alt text depending on where and how it is used.
4. Skip unnecessary wording.
Don’t write “image of” or “picture of.” Instead, simply describe what’s important. Exception: If it's a logo, illustration, chart, graph, painting, or cartoon, identify it.
5. Always review AI-generated alt text.
Many platforms—including Canva, Hootsuite, and other tools—can generate alt text automatically. They're a great starting point, but they're not always accurate.
Alt Text Example
Too vague: Students outside.
Better: Elementary students planting vegetables in a school garden for science class.
It explains why the image matters, not just what it shows.
Best Practices
- Add alt text to images on your website.
- Add alt text to images when scheduling and publishing social media posts.
- Include alt text in newsletters and other digital communications.
- In PDFs, mark decorative images (e.g., shadows, decorative lines and shapes) as decorative so screen readers can skip them.
Need help creating accessible communications?
Learn more about our school communication services and accessibility resources. Scan the QR code or visit www.donovan-group.com.
This resource was developed using guidance from Harvard University Information Technology's accessibility resources, adapted for K-12 school communications.