Alt text for images: how to write it well

Alt text is the short description behind every image. You hardly ever see it, which is exactly why it gets forgotten. Yet good alt text takes only a few seconds per image and helps twice over: people who cannot see your page, and search engines.

What is alt text?

Alt text (“alternative text”) lives in the image’s alt attribute in the HTML. It stands in for the image when the image cannot be seen: screen readers read it aloud to blind and visually impaired people, and browsers show it when an image fails to load.

Why alt text matters

• Accessibility: Without alt text, a screen reader user has no idea what the image shows, or in the worst case hears the file name read out. Since 28 June 2025, the European Accessibility Act has also made accessibility a legal requirement for many online shops in the EU.
• Search engines: Google uses alt text to understand what an image shows and how it relates to the page. This helps especially in image search.
• When images are missing: If an image does not load, for example because its source is offline, at least the description remains.

Good and bad examples

Six rules for good alt text

1. Describe what matters. Not every detail, but what the image is meant to say in this spot.
2. Short and specific. A sentence or a phrase is usually enough. A common rule of thumb is around 125 characters.
3. No “image of …”. The screen reader already announces that it is an image.
4. No keyword lists. A search term is fine if it fits. Strings of keywords help no one and can even hurt.
5. Text in the image belongs in the alt text. If a graphic contains text, the alt text must include it.
6. Links describe the destination. If an image is a link, say where it leads.

Decorative images: empty alt text

Purely decorative images, such as background patterns, dividers or an icon next to text that says the same thing, get an empty alt text (alt=""). Screen readers then skip them. Important: empty is not the same as missing. If the attribute is missing entirely, some screen readers read out the file name instead. The W3C’s alt decision tree helps you decide.

How to manage alt text in WordPress

• When inserting: Click the image in the editor. You will find the “Alternative text” field in the sidebar on the right.
• In the Media Library: Go to Media → Library, open an image and enter the alt text there. It is used when you insert the image afterwards.

Take a close look after a migration or import

When you bring images over from an old system or import external images into the Media Library, you often end up with alt text that describes nothing: file names like IMG_4711, placeholders like “Image from https://…” or nothing at all. None of this shows on the front end, so after every migration it pays to go through your most important pages. Start with the pages that get the most visitors.

Quick checklist

• Does every meaningful image have alt text?
• Does it describe what the image says in this spot?
• Do purely decorative images have an empty alt=""?
• Is text from graphics included in the alt text?
• Do linked images say where they lead?
• Are there no file names or placeholders left over after an import?

Frequently asked questions

Is alt text the same as the image title?

No. The title (title) shows up as a tooltip in some browsers and is usually not read out reliably by screen readers. For accessibility and search engines, the alt text is what counts.

What about the caption?

Everyone sees the caption. It adds to the image but does not replace the alt text. Do not repeat it word for word in the alt text, or a screen reader user will hear the same sentence twice.

Can AI write alt text?

As a suggestion, yes, and it saves time. But check the result: an AI does not know why you are showing the image in exactly this spot.

Sources: W3C Web Accessibility Initiative: Images Tutorial, Google Search Central: Image SEO best practices.