Alt text is a concise written description of an image that makes it accessible. It primarily benefits blind or low-vision individuals who rely on screen readers to understand visual information. Neurodivergent learners and the general population may also find it useful in understanding the most salient aspects of an image. Alt text enables screen readers to read the description aloud so that users can understand the image. 

Alt Text: Best Practices 

• Be concise and descriptive. Convey essential information (subject, setting, actions, interaction, and the purpose of the image in 120-150 characters. Do not repeat information that is in the surrounding text. 
• Do state if it’s a logo, illustration, painting, or cartoon, but avoid writing “image of” or “picture of,” since the screen reader will add that automatically. 
• If an image is decorative, check the “decorative” box. If no checkbox exists, enter the word “decorative” as the alt text. 
• If using AI to generate alt text, review it for accuracy and ensure it reflects the image’s intended purpose and function. 
• If it is an image of words, include the "words" in the alt text  
• Consider special situations (images of charts/graphs, art, longer alt text needs, etc.). See "Specialized How Tos" below. 
• End the alt text with a period to signal to the screen reader. 

Alt Text: Examples 

Effective: Researcher preparing specimens for alpha-spectrometry testing in a lab. 

• Concisely conveys relevant information     

Ineffective: Image of researcher preparing specimens for alpha-spectrometry testing in a lab.  

•  Includes “image of”, so that a screen reader would read it as “Image of image of .... 

Ineffective: Man standing in a white coat. 

• Does not convey why image was included in this context.  

How to Apply Alt Text  

• In Microsoft Word and PowerPoint 
  • Everything you need to know to write effective alt text (read) 
  • Add alternative text to a shape, picture, chart, SmartArt graphic, or other object (read) 
  • Improve accessibility with alt text (watch) 
• In Canvas 
  • How can I make images more accessible? (read) 
  • How do I manage Alt Text? (read/watch) 
• Remember: Check Accessibility of Course Content 

Specialized How-To's 

• If an image is very detailed and requires a longer description, include a short description in the alt text. Beneath the image, provide a link to the data table or a longer description of the graphic.  
• Description Templates for Common Graphics pie charts, bar graphs, and more 
• How to Describe Complex Images art, math, science diagrams, maps, tables, and more  
• Core Aspects of a Description for artistic images and nuances of color, size, etc 
• Image Descriptions for Assessments to avoid bias in a testing environment  

Where can I get support or further training? 

Faculty Learning and Support Opportunities

For faculty developing and managing website content, refer to:  

• Web Accessibility Tutorials  
• W3C’s Images Tutorial for coding alt text on webpages 
• Authoring Meaningful Alt Text for backgrounds, control buttons, icons 

References 

W3C. (2024). How to Meet WCAG-Quick Reference.