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Alt text decision treeDoes this image need alt text?

Answer up to four questions. Get the right kind of text — or none — and the markup to paste.

Does this image need a sentence at all?

The questions the W3C decision tree asks, in its order, until one settles it. They set what the checker expects; leaving them alone changes nothing.

Is this image inside a link or a button?

A logo that goes to the home page, an icon that submits a form, a thumbnail that opens an article. If it is clickable and the picture is the whole of the control, answer yes.

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A woman at a library table looks through a magnifier at a spread of printed photographs.
DecisionInformative photo: say what it shows, in one sentence.The W3C decision tree
Checked in this tab. No photo and no alt text is sent.

The questions are the W3C’s, in its order: is the image a link or a button, does it carry information the words around it do not, is it a chart or diagram, is its information mostly text. A question the earlier answers have settled is not asked. Five answers are possible, and each comes with the markup it calls for.

Why ask before writing

The two worst outcomes in alt text both come from skipping this step: a decorative flourish described at length, which makes a listener sit through nothing, and an image that is the whole of a link given an empty alt, which leaves them with a control that announces nothing. Neither is a writing problem. Both are answered by deciding what job the image does before deciding what to say about it.

The tree here is the one the studio asks with a picture open, on its own, for auditors and editors working down a list of images. Each answer comes with the markup to paste and a line for your audit notes.

What it will not do

  • It does not look at the image or write the alt text — it tells you which kind of text the image needs.
  • It does not certify a page as accessible or produce a conformance report.

Questions people ask

Where do these questions come from?

From the W3C Web Accessibility Initiative's alt decision tree, in its order. A question the earlier answers have already settled is not asked: an image that is the whole of a link ends the tree at once, a decorative one after two questions, a chart after three.

What are the five answers?

Decorative (an empty alt attribute, alt=""); a link or button (name where it goes, not what it looks like); a chart, diagram or map (a short alt plus a long description near it); an image of text (the words are the alt); and an ordinary informative picture (say what it shows, in one sentence).

Is an empty alt the same as no alt?

No. alt="" tells a screen reader to pass over the image silently. Leaving the attribute out makes many screen readers read the file name instead, which is the worst of both.

How do the audit notes work?

After each answer, type which image it was (a file name or URL) and an optional note, and add it. The list builds up one line per image and can be copied as a Markdown table or downloaded as Markdown or CSV for an audit report. It lives in this tab only.

Do I need to upload the image?

No. The tree asks about the image's job on the page, not about its pixels, so no picture is needed.

Where to take this next

Photographic visual for Alt Text Decision Tree
In this toolAlt Text Decision Tree