A Picture’s Worth… 120 Characters?
From the Quick Access series
April 2026 marks the federal deadline for digital accessibility under ADA Title II. At UC Davis, our commitment to accessibility will honor both the mandate and our Principles of Community as we remove barriers for all learners. Part of a series to be published during the fall of 2025, this post explores what accessibility means in practice and ways we can all contribute. Find all the posts in this series by clicking the yellow "Quick Access" label at the end of the post.
For more on campus compliance with this law, see UC Davis Digital Accessibility Program Manager Brad Starkey-Owens’ conversation on digital accessibility with Dr. Andy Jones and check the campus Accessibility site. Also consider joining the UC Accessibility Project or registering for the Universal Design for Learning Institute this fall (held each Friday this fall at 10:30AM on Zoom) for additional accessibility support.
Alternative text—or alt text—describes the content and purpose of an image, graph, chart, or other visual. It fulfills WCAG 2.1 Success Criterion 1.1.1 (Non-text Content), which requires text alternatives for meaningful visuals. Alt text is embedded in code, so it isn’t visible on screen. Instead, screen readers read it aloud for blind and low-vision users. Without alt text, a screen reader has nothing to announce when it encounters an image—it simply skips over it.
There’s no single formula for perfect alt text, but these guidelines can help:
Be concise.
Alt text isn’t a detailed account of every element in an image – include only what’s relevant to your learning goals. Canvas also limits alt text to 120 characters (any more than that will trigger an error message), so focus on what students truly need to know.
Consider your learning objectives.
Why are you using this image? Is it decorative or instructional? How will students engage with it? An art historian, French instructor, and political scientist could all use the same Delacroix painting but would each write different alt text to align with their teaching goals.
Avoid redundancy.
If you describe the image elsewhere, such as in a paragraph near the image, don’t repeat that same information in the alt text and force screen reader users to hear the same information twice.
Mark decorative images properly.
If an image is purely aesthetic, mark it as decorative so screen readers skip over it and so users aren’t distracted by unnecessary details.
Thoughtful alt text makes course materials more inclusive, ensuring that all students can access your content equally.
