Users with certain disabilities will be unable to see images and/or comprehend the content they are meant to convey. Alternative text can help give context and meaning to an image.
When to Add Alternative Text Descriptions for Images
- Simple image with simple meaning - Add descriptive alternative text of 10 to 169 characters as outlined below. The alternative text should describe the educational/informational purpose of the image.
- Complex image with rich meaning - Add a paragraph above or below the image that goes into more detail. Some pointers, such as Next image or Previous image, will help create cohesion between images. If the image is referenced from elsewhere in the document, add a caption below the image, and reference the caption. If the longer alternative text is not feasible, create a link to an external Web page that contains an appropriate description.
- Decorative image - If the image is purely decorative or used for visual formatting, the alternative text description should be left blank to hide it from users of assistive technology.
Examples of Text Alternatives for Images
The following provides examples of length and specificity for text accompanying images:
- Alternative Text: Scientist in a lab filling a vial with fluid
- Description in the text before or after the image: The next/previous image shows a female forensic scientist who is filling a vial containing a small amount of blood with fluid to denature the sample as part of the process of the PCR analysis method of DNA profiling. In the background is a centrifuge, which will aid in the process of extracting the DNA from the sample of blood.
- Reference in the body of the document: "... Figure 1.3 shows the correlation between the...." [Image] Figure 1.3.
Steps to Add Alternative Text to a Newly Embedded Image
- If an image is not already embedded in the text box, select the Image icon in the Rich Text Editor toolbar to insert an image. The Image icon displays a picture that looks like a landscape, with mountains and a sun. For more information on adding an image, please see the article Embedding an image in a text box.
- In the Image Properties dialog window, enter short and meaningful descriptive text in the Alternative Text box.
- Select OK to confirm the addition of the text.
Steps to Add Alternative Text to an Existing Image
- Select the image you have embedded in the text box.
- Select the Image icon in the Rich Text Editor toolbar. (The Image icon displays a picture that looks like a landscape, with mountains and a sun.)
- In the Image Properties dialog window, enter short and meaningful descriptive text in the Alternative Text box.
- Select OK to confirm the addition of the text.