Painting Pictures with Words
- What: Alternative text (Alt Text) is a brief, written description of an image. It is read aloud by screen readers and displayed if an image fails to load.
- Why: For users with visual impairments, Alt Text is the only way to understand the content and function of images. Without it, a screen reader may simply say “Image” or read out a cryptic file name like IMG_9823.jpg.
- When: Every image, chart, and icon needs Alt Text—unless it is purely decorative (like a background flourish).
- Check: Right-click an image in your document. If the Alt Text field is empty or contains a file name, it needs attention.
Accessible Writing Tip: How to Write Great Alt Text
How to Write Great Alt Text
Alt text should be accurate, concise, and context-aware.
The Phone Test: Imagine you are describing the document to someone over the phone. What would you say about the image to make sure they don’t miss the point?
- Be Concise: Aim for 125 characters or fewer. Most screen readers stop reading after that.
- Context Matters: A photo of a “Student in a blue shirt” is fine, but if the article is about graduation, “Senior student celebrating at Spring Commencement” is better.
- Avoid Redundancy: Don’t start with “Image of…” or “Photo of…” The screen reader already identifies it as a graphic.
- Decorative Images: If an image adds no information (e.g., a divider line or a generic stock photo of a cloud), mark it as “Decorative” so the screen reader skips it.
- Link Images: If the image is a link (e.g., a button that says “Register”), the Alt Text should describe where the link goes (e.g., “Register for the Accessibility Workshop”) rather than what the button looks like.
- Complex Images (Charts and Graphs): If an image is too complex for 125 characters (like a data chart), write a short alt text like “Line graph showing the 10% increase in student enrollment from 2020 to 2026” and a full description directly on the page either as the raw data in a table or a text paragraph immediately after the image.
- No Punctuation: your alt text descriptions should be free of punctuation like commas, quotes, or periods.
Mastering Web Accessibility: Image Descriptions
The following video has some tips on how to write alt text depending on the type of image: decorative, nice to have, or essential.
Add Alt Text to your Images
Microsoft Word and PowerPoint
In Microsoft Word and PowerPoint Right-click any image and select View Alt Text. If you use the “generate a description for me” option, always proofread and edit the content before saving.
The following support page from Microsoft details how to add alt text your documents. You can also review the following support page for additional details Accessibility Resources and Tutorials: Microsoft Office.
Google Docs and Slides
In Google Docs and Slides, Right-click the image and select Alt Text (or press Ctrl+Alt+Y). Add your description to the “description” field and not the “title” field.
For more information the following support pages for additional details Accessibility Resources and Tutorials: Google Docs and Accessibility Resources and Tutorials: Google Slides.
Canva
Select an image, click the “i” (Info) icon, and select Alternative Text. If you are using a purely decorative element, leave the text box empty or check “Mark as decorative.”
You can also review the following support page for additional details Accessibility Resources and Tutorials: Canva.
Adobe Acrobat
- Note: Editing images directly in a PDF is complex and prone to errors.
- The Golden Rule: Always fix accessibility in the source file (Word or Google Docs) before exporting to PDF.
If you must edit a PDF without the source file, we recommend exporting it back to Word first:
To export PDFs to Microsoft Office:
- Open a PDF file
- Choose the Export PDF tool
- Choose format and select Export
- Save your file
Resolving Image Errors in PDF
If you still have image errors in your PDF, you can use the Accessibility tools to add alt text.
From Adobe Tools, select Accessibility > Accessibility Check > Start Checking. If you have images that are missing alt text, you can select them from the accessibility report, right-click and select Fix.
Web Platforms
If you are uploading images to a web platform such as WordPress or Canvas, you can add alt text by reviewing the image settings.
The "Big Five"
In documents, the following areas are often the biggest challenges for accessibility. As a bonus, if your document has tables, be sure to pay extra attention to them. Learn more about these five areas and how you can build from accessibility from the beginning.