Writing Better Alt Text

Alt text helps people using screen readers understand images and other visual content on your page. Well-written alt text improves web accessibility by communicating an image's purpose, not just what it looks like.

Note: This tip applies specifically to content images (images inserted into the page content area).

Describe What Matters

Before writing alt text, ask yourself: Why is this image on the page? Focus on the information the image adds to the page, not every visible detail. Not every image requires the same amount of detail. The examples below show when to write more, write less or not write alt text at all.

Example 1: Too Little Information

Less effective
Person using a microscope.
More effective
Researcher examines a sample under a microscope.

Remember: Describe the information the image adds to the page.

Example 2: Too Much Information

Less effective
Student wearing a green William & Mary sweatshirt, jeans and white sneakers smiles while carrying a backpack across the sidewalk.
More effective
Student walks across campus.

Remember: Focus on the meaningful details.

Example 3: Decorative Content Images

In this example, a content image is used only to add visual interest and doesn't add to the page's content.

Less effective
Add descriptive alt text.
More effective
Mark the image as decorative.

Remember: If a content image doesn't add information or meaning, mark it as decorative instead of writing alt text.

Quick Checklist

Before adding or updating alt text, make sure it:

Describes the image's purpose.
Includes meaningful details, but not unnecessary ones.
Doesn't begin with "Image of..." or "Photo of..."
Isn't repeated in nearby text.
Is marked as decorative if the content image doesn't add information or meaning.

Other Images in Cascade

While the principles for writing effective alt text for other images are the same, whether the alt text you include on the image file is used, or the image is treated as decorative, is programmatically determined.