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D4D Accessibility Guide

Milestone Overview: Alt-Text for Images

Images have alternative text (alt-text)

Alt text is a concise description of the image. Screen reader users won’t be able to engage with an image you put into your guide unless it has alt-text.

Accessibility Best Practices

Check each page for your guide to make sure all images have alternative text. 

  • You can do that in the author edit mode of each page by clicking on each image (probably the most practical).
  • Do an automated scan with an accessibility checker.
    • Check each page of the guide. Note down which images don’t have alt-text
    • Use the editor in LibGuides to add alt-text. 


You can also do a scan of a page after you’ve done the work just to confirm you haven’t missed anything

  • Use the Rich Text Editor > Image tool or use the Image Manager found via Main Menu > Content > Image Manager
    • Image Manager Note: There’s currently a vendor bug that limits the character count to 50, so be aware of that if you’re describing complex images. Use the rich text editor for longer descriptions.

Writing Alt-Text:

  • Describe what's in the image as best you can. Think about what information does that image convey to the viewer/
  • Try to keep it short (~140 characters) because a user has to listen to it. Too wordy and it can be overwhelming. 
  • Use punctuation in your alt-text. Make sure to put a period at the end of your sentences. Punctuation helps screen readers pace.
  • Remove images that are purely decorative, serve no educational, or communications purpose. Or add “” into the Alt-Text field (no spaces between the quotation marks). 


  • If you have marked-up screenshots in your guides to explain how to use an online service or system be aware that the text or arrows you add to that image won’t be available to a screen reader.
  • The best practice is to write out the information or directions in the body text of your guide, not just on an image, that way it's accessible to everyone. 
  • Having directions in your body text makes writing the alt-text for that image and keeping to the 140 characters much easier. 

LibGuide Help Center Resources:

Additional Resources

Project Management Suggestions

  • Run specific workshops for creating alt-text. We got a lot of questions about it and because it's more of an art than a science giving people the opportunity to practice and learn as a group proved helpful.
  • Reach out to authors of guides related to the visual arts early about alt-text. They may be a great asset for helping your organization think about describing images and developing resources and best practices.