Image Alt Text A: Basic Images & Charts

Overview

Alt text (short for alternative text) is descriptive text added to images in digital content (like websites, documents, or learning platforms). It serves several important purposes:

• A written description of the image’s content, purpose, or function.

• Read aloud by screen readers for people who are blind or visually impaired.

• Displayed in place of the image if it doesn’t load.

• Describes an image for users who can’t see it — including people using screen readers, people with low vision, and users on slow connections. It ensures everyone can understand the image’s content or purpose.

✅Checklist for Image Alt Text

1. Is not the file name

2. Describes the essential content or function of the image

3. Is brief and clear (under ~125 characters for most images)

4. Matches the context and purpose of the image (A photo in a biology course might be “Leaf cross-section showing veins and stomata,” while the same photo in a design course could be “textured green maple leaf with gray shadow.”)

5. Avoids redundant phrases like “image of” or “picture of” (screen readers already announce it’s an image)

6. Is skipped entirely if the image is purely decorative

7. Includes relevant data if the image is informational (e.g., chart) 

Alt text examples for image above:

✅  A man and a woman sitting next to each other at a table laughing.

❌ A man and a woman.
→ Not enough detail

❌ Picture of a woman in a mustard sweater with a cup of coffee in front of her next to a man with a beard and wearing a blue shirt in front of a laptop. There is a corkboard and a bookshelf in the background and daylight seen through an outside window.
→ Too long (256 characters) with unnecessary details

Mark Images as Decorative if…

• It’s just borders, patterns, stock visuals with no context

• It doesn’t contribute to understanding the content

• It repeats information already given in nearby text

✅ Checklist for Alt Text and Basic Charts

• Include type (chart, pie, etc) title, dates

• Consider adding an (accessible) data table version below the image. This lets users access raw data directly.

• Summarize the key insight (s)

Sample Alt Text for image above

The bar chart compares 2024 first-quarter sales in North America ($1.2M), Europe ($950K), and Asia ($1.5M). Asia leads with the highest revenue, showing a 25% increase over the previous quarter. Sales increased in all regions, with Asia showing the most growth. 

See the page "Alt Text B: Complex Images" for information about making those resources accessible

Besides options described in the Accessibility Tools in Canvas page, you can use the (Ally) icon that appears in the bottom left of all uploaded images to add/edit the alt text. 

Another option: Click your course Files tab. Do a search for "jpg" and then "png." Canvas will populate a list of all those file types. Use the Ally icons in the Accessibility columns to add/edit alt text. *While there, delete any unpublished or unused files!