Creating image descriptions (Alt Text)

Information on how to determine image descriptions Alt Tex example: The orbiting paths of the 8 planets in our solar system.

Image descriptions, also called Alternative Text (Alt Text) are read by screen readers to provide information gleaned from images for students with visual impairments and blindness.  Image descriptions provide all students - including those with visual impairments - with equal access to image-rich digital texts.  All digital materials should have image descriptions to be accessible - especially digital materials used in the classroom!  Image descriptions can easily be added to pictures.  The Diagram Center and WebAim are two leaders in standardizing how images should be described.  When creating image descriptions, consider these general guidelines:

  • Context is Key
  • Consider Your Audience *
  • Be Concise
  • Be Objective
  • General to Specific
  • Tone and Language 

* Teacher Hint: Consider Your Audience.  Much of the information about image descriptions is geared for adults.  It is important to consider the student age/grade level when creating descriptions for students. 

  • Know your target reader (e.g. age, culture, subject-matter, expertise).
  • Use vocabulary and phrases appropriate for the reader.
  • Reference examples and details that the reader will understand (this includes objects and attributes used in the description)

Teacher Hint: When an image is an  "extra" and does not relay important information, the image can be marked so that the screen reader ignores the image.  (Example:  With a Windows Word document, typing two quotes in the alt text textfield will tell the screen reader to skip the image.)  Keep in mind that when working with curious students, a student may want to know the "extra" or fun information. (Example:  Image of Pokemon on a homework assignment.  The student knows all about the Go Pokemon app craze, but does he/she know what Pokemon looks like?)

Diagram Center's Image Description Guidelines - Detailed instructions on image descriptions.  This website does look at image descriptions for students.  The website provides sample pictures taken from textbooks - including elementary and middle school textbooks, image descriptions and explanations about the chosen image descriptions.  This website includes General Image Description Guidelines and Specific Image Description Guidelines.  

Example of a web diagram with it's corresponding image description.Image Description:

A web diagram has a center circle and five smaller circles connected to it.  The center circle is labeled Scientific Methods.  One connected circle is labeled Observation. The other four circles are labeled A, B, C, and D.


Teacher/Braillist Hint: Teachers of the visually impaired and paraprofessions should provide image description and accessibility training to their students' regular education teachers.  Regular education classroom teachers can and should include image descriptions on the basic images included in the materials that they use in the classroom.   However, with the more complex diagrams, these teachers may need additional training or assistance to create quality image descriptions for complex diagrams.  The Diagram Center website is a wonderful resource on how to create image descriptions for complex diagrams.

The Diagram Center's Specific Image Description Guidelines include:

  • Art, Photos & Cartoons
    • Drawings & Paintings
    • Photographs
    • Cartoons & Comics
  • Chemistry
    • Chemical Element
  • Diagrams: Illustrated
    • Comparing Objects
    • Comparing Object, Complex
    • Comparing Events Over Time
  • Diagrams: Relational
    • Venn Diagrams
    • Radial/Web Diagrams
    • Hierarchy/Tree Diagrams
    • Flow Charts
    • Cycles
  • Graphs
    • Bar Graphs
    • Line Graphs
    • Pie Graphs
    • Scatter Plots
  • Maps
    • Geographic Maps
    • Political Maps
  • Mathematics
    • Graphs
    • Math Diagrams
    • Geometry
    • Equations & Expressions
  • Tables
    • Simple
    • Complex
  • Text Only Images
    • Nutrition Labels
    • Timelines

WebAIM information on Alt Text - WebAIM is specifically for image descriptions of pictures found on the web; the information found on this website is appropriate for all image descriptions, not just web images.  WebAim includes examples of common blunders, explanations of why these descriptions are not the best and then more appropriate descriptions.

Creating Alt Text For Images and Objects: Windows post - discusses how to create Alt Text in Word on a Windows computer.

Learn How to Create Accessible Word Documents post - discusses creating accessible Word Documents including Alt Text.

Creating Accessible PowerPoint Presentations for Students with Visual Impairments and Blindness post - discusses how to create Alt Text for PowerPoint Presentations.

How to Create an iBook using iBook Author App post - discusses how to create an accessible iBook, including pictures with Alt Text.

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