If you use a Mac, click this link to go to the Word 2016 for Mac module.
Besides text, many Word documents also contain images. The overall purpose of including images in a document should be to help the reader comprehend the purpose and/or meaning of the content they are reading. Some of the most common image types used within documents are:
Screen-reading software can only read text, not images or non-text graphics. Therefore, a reader who cannot see your document will only learn that there is an image there, not what the image is or what function it serves in the document.
Adding an alternative text description, also known as alt text, to the image alerts the screen-reading software that there is text to read aloud. When the screen reader passes over the visual element, it will read the alt text.
Alt text also makes web pages more accessible to anyone who is browsing on a
weak internet connection or a small portable device like a smart phone. The alt
text labels become visible while images are loading.
Alt text should not repeat what is already stated in captions or other document text. Think of it as a secret code that only screen reader users will be aware of. It will not appear to the naked eye, but rather is part of the document's code. Consider the following example:
Caption: In this painting the artist Emanuel Leutze used light and color to convey motion.
Notice that the caption does not really describe WHAT the image is. Add in alt text to give a description of what we see here. Maybe something like:
"George Washington looks forward with a determined gaze as his wary troops row their small craft across the Delaware River and into battle. The light of dawn, swirling water, and jagged icebergs add a dramatic effect."
(For Word 2016 instructions, scroll further down the page)
In the "Alt Text" window that appears to the right, fill in 1-2 sentences describing the image. ** For images that would require a longer description, consider providing a link to a Word document above the image.
Here is a video to show how to add alt text to a document in Word 2016 for Windows (PC).