What is alternative text?
Alternative text (alt text) is a short written description that communicates the purpose or meaning of an image. Screen readers read alt text aloud, allowing people who are blind or have low vision to understand what the image conveys in the context of your content. Alt text also appears if an image doesn’t load, ensuring important information isn’t lost. Everyone can see alt text, so adding it provides extra context and clarity, improving understanding for all users, not just those using assistive technology.
Why does alt text matter?
Alt text is essential because it gives screen reader users access to the information conveyed by images. Without it, people who are blind or have low vision may miss important context or meaning that sighted users see instantly. By providing clear, descriptive alt text, you make sure all users can fully understand and engage with your content.
How do I write alt text?
To write effective alt text, be concise but descriptive, focusing on the image’s purpose rather than just its appearance. Include important details or text the image conveys, and avoid unnecessary phrases like “image of.” It's often helpful to ask yourself these questions before writing alt text:
- Why did I include this image?
- What's the main takeaway of this image?
Example: “Butler Blue, wears a blue sweater with a white “B” on it. He sits on the basketball court, looking directly at the camera with his tongue slightly out.”
What about images that are purely decorative?
If images are purely decorative and don’t add meaning to the content, they should be marked as decorative. This tells screen readers to skip the image, preventing unnecessary interruptions for users. Decorative images can still enhance design, but they shouldn’t distract from the main content or create extra noise for those using assistive technology. Most platforms (Word, PowerPoint, Google Docs, Canvas) have checkboxes to mark images as decorative.
How do I add alt text?
To add alternative text to images, please see the resources below:
