Images
In this section, we provide recommendations to guide your inclusion of accessible, image-based content.
What Are Images?
Before you can determine what you need to do to make an image accessible, you first need to identify its purpose or value to your textbook. Consider the following questions:
1. Does your image serve a functional purpose? In other words, is it conveying important non-textual content to students? If so, you should:
- Provide an alternative text description (alt text) that serves the equivalent purpose of the non-text material.
- Not use colour as the only visual means of conveying information (W3C, 2008).
2. Does your image serve more of a decorative purpose? In other words, is it primarily a design element that does not convey content? If so, you should:
- Avoid unnecessary alternative text descriptions
Who Are You Doing This For?
This work supports students who:
- Are blind or have low vision
- Have poor contrast vision
- Are colour blind and cannot differentiate between certain colours
- Are using a device with monochrome display
- Have a form of cognitive disability
What Do You Need To Do?
Functional Images and Alternative Text Descriptions
Consider what your content would look like if the images didn’t load. Now try writing alternative text for each image that serve as a replacement and provide the same information as the image.
As you work on developing your alternative text descriptions, keep the following recommendations and guidelines in mind:
- Alternative text should convey the content of the image and its purpose (WebAIM, 2014).
- Try to keep your text descriptions short (less than 125 characters). You should aim to create a brief alternative (one or two short sentences) that is an accurate and concise equivalent to the information in the image.
- For more complex images requiring longer descriptions(e.g., detailed charts, graphs, maps), you can either provide the details in the text surrounding the image or provide a link to a longer text description on a separate page. You should still include a short text description that gives the image a meaningful name and tells students how to access the longer description.
- Leave out any unnecessary information. For example, you do not need to include information like “image of…” or “photo of…”; assistive technologies will automatically identify the material as an image, so including that detail in your alternative description is superfluous.
- Avoid redundancy of content in your alternative description. Don’t repeat the same information that already appears in text adjacent to the image.
Example (from Introduction to Sociology):
This photograph could be described in this way in the alternative text description:
Includes one photo of crowded, shabby buildings on a hillside and another with magnificent buildings located by water.
How to Add Alternative Text Descriptions
When Editing Images added to content in Pressbooks, provide alternative text descriptions in the box