Accessible Images = “Alt” Text Required
To create accessible images, those meant to convey meaning must have an alternative or “alt” text description. Since images are “unreadable” content, screen readers will read the alt text description when an image is found.
If no alt text is assigned to that image, then an accessibility error will appear (in Word documents and Canvas). This error occurs because students need a description of that image if they cannot see it.
Decorative images, by contrast, add no meaning to your content. Typically, we hide decorative images from screen readers since they add no value to students’ learning experiences.
- If you distribute a Word document, students will encounter all images when traversing the document. Thus, you should insert “decorative” into the alt text for all decorative images. This word tells students they are not missing anything if they cannot see those images.
- If, however, you want to provide that document as a PDF, check the box that says “Mark as decorative.” Then, their screen reader will skip over the decorative image(s) when they traverse through the PDF.
How to Write Alt Text
Guidelines — Alt Text Should:
- Be accurate and equivalent – present the same content or function as the image
- Be succinct – a small phrase or a sentence. It’s best to keep this at 100 characters or less.
- End with a period (.) so screen readers will pause after reading the description
- NOT be redundant – don’t provide info already in the surrounding text
- NOT use phrases like “image of…” or “graphic of…” Screen readers already state when they encounter a “graphic.”
Writing Alt Text Resources
- Alternative Text Guide (WebAIM)
- Image Alt Text Best Practices (Siteimprove)
- Context is Critical for Alt Text
- Poet Training Tool: Helping You Write Effective Image Descriptions
Alt Text Examples
Possible Alt Text for this image:
- Man who is blind walks with his cane and carries his guitar to practice.
- Man who is blind walks using his cane down a busy street in Puebla, Mexico. Signs and graffiti circle the post behind him.
- Visually-impaired pedestrians can now walk safely, given metal rails installed on Mexico sidewalks.
Any of these examples could work for this image, but the text you choose should depend on the surrounding content. What is essential for your students to know about your image?
Adding Alt Text to Microsoft Office & the Web
- Word 365 & PowerPoint 365
- Word 2019 & PowerPoint 2019
- Word 2013/2016 & PowerPoint 2013/2016
- Word 2010 & PowerPoint 2010
- Writing Alt Text for the Web
In summary, images meant to convey meaning to your students should always include corresponding alternative (“alt”) text. In contrast, decorative images—those that add no meaning to your content—should be hidden from screen readers or marked “decorative” for their alt text.
Including alt text for your images ensures you do not create barriers to your content but provide access to all that need it.
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