How to Write Alt Text for Images

What this means

Alt text (alternative text) is a short written description of an image, stored in the page's code. Visitors never see it unless the image fails to load. Screen readers read it aloud, and search engines read it to understand the picture.

A site audit flags pages where one or more images have no alt text.

Why it matters

People who are blind or have low vision use screen readers. Without alt text, an image is announced as "image" or by its file name, such as "IMG_4471.jpg". That's a poor experience, and accessibility law in many countries expects better.

Google can't see pictures the way people do. Alt text is one of the main ways it understands what an image shows, which affects whether your images appear in Google Images and helps the page's relevance.

How to write good alt text

Describe what the image shows, as you would to someone on the phone. Keep it short: one sentence, usually under 125 characters.

• Good: "Sourdough loaf with a dark, crackled crust on a wooden board"
• Too vague: "bread"
• Stuffed with keywords: "sourdough bread Leeds bakery best sourdough Leeds"

A few rules of thumb:

1. Don't start with "image of" or "picture of". Screen readers already say it's an image.
2. Include the words that matter for the page if they fit naturally, such as the product name.
3. For an image with text in it, such as a banner or a chart, include the important text or the chart's main point.
4. For a logo, the company name is enough.
5. Purely decorative images, such as dividers or background patterns, should have empty alt text so screen readers skip them. Most builders have a "decorative" option for this.

Where to add it

• WordPress: open the Media Library, click the image and fill in "Alternative Text". In the block editor, select the image and use the box in the sidebar. Setting it in the Media Library covers new uses of that image, but images already placed on pages may need updating on the page too.
• Shopify: open a product's media, click the image and choose "Add alt text". For images in theme sections, look for an alt text field in the section settings.
• Wix: click the image, choose Settings, and fill in "What's in the image?".
• Squarespace: edit the image block and add a description in the image's settings, or use the filename field for some gallery types.

Doing a lot at once

Start with the pages that matter most: your home page, main services and best-selling products. Gallery pages often have dozens of images; it's worth doing them, but they can wait until the important pages are done.

Checking your fix

Right-click an image, choose Inspect, and look for alt="..." with your text in it.

If you use Duality, tick the page in Site Audit and choose Verify my fixes to check it again straight away.