How to add alternate text to an image in InDesign
Today’s post explores adding alternate text to images in Adobe InDesign. It came out of a conversation I had with Colleen Gratzer.
Alt text plays an essential role in document accessibility. It allows screen readers to describe meaningful images so people who are blind or have low vision can access the same information as other readers.
This post is an outtake from my podcast episode with Colleen, where we focused on why designers should incorporate accessibility best practices during the production phase rather than as a last-minute fix at the end.
Video Guide
When Does an Image Need Alt Text?
Before adding alt text, determine whether the image communicates information.
Decorative images do not require alt text because they do not contribute meaning to the content. Background graphics, borders, and other purely visual elements should remain decorative so screen readers can skip them.
Informative images should include alt text. These include photographs, charts, diagrams, illustrations, maps, and other visuals that help readers understand the content.
Add Custom Alt Text in InDesign
InDesign makes it easy to add custom alt text to an image.
Select the image, right-click (CTRL- click on Mac)>Object Export Options>Alt Text>Custom. Then enter a description that explains the purpose or meaning of the image.
InDesign includes your custom alt text when you export the document as an accessible PDF.
Beware the AI-Generated Alt Text Feature
InDesign 2026 automatically generates alt text when you place images. The feature may save time, but you must review every description to ensure it matches the image’s purpose and surrounding content.
To turn this off: Preferences > Generative AI. Toggle off the option to automatically generate alt text when placing images.
WARNING: In shared documents, different settings can cause problems. If one person writes custom alt text and another opens the file with automatic generation enabled, InDesign may replace the original descriptions.
Reviewing Alt Text
InDesign doesn’t provide a central panel for reviewing alt text, so checking images one by one can take time, especially in large documents.
A script developed by Dax Castro exports all image alt text to a spreadsheet, making it easier for editors, translators, and clients to review and update descriptions.
Before publishing, review your exported PDF with an accessibility tool such as Callas PDFGoHTML. It displays the document structure, image tags, and associated alt text so you can verify that everything has been exported correctly.
Alt Text Best Practices
Keep these principles in mind when writing alt text:
- Describe the purpose of the image, not every visual detail.
- Keep descriptions concise and relevant.
- Consider the surrounding content when writing the description.
- Leave decorative images without alt text.
- Review automatically generated descriptions before publishing.
- Test exported PDFs with accessibility tools and screen readers.
Creating accessible documents requires thoughtful planning and careful review. By writing meaningful alt text, maintaining consistent workflows, and verifying your documents before publication, you will provide a better experience for everyone who relies on assistive technology.
Let me be your champion for inclusion. I offer tailored solutions (and self-paced courses!) to ensure your documents meet and exceed compliance expectations. For more detailed insights, tutorials, and in-depth discussions on accessibility and related topics, don’t forget to check out my YouTube channel: The Accessibility Guy on YouTube. Subscribe for regular updates!
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