Image Alternatives Equivalent
Group: images-and-media • Guideline: image-alternatives
Summary in Plain English
The text alternative has to serve the same purpose as the image, not merely describe its appearance.
Why It Matters
"Photo of a chart" tells a blind reader that information exists and withholds it. The alternative has to carry what the image is there to convey.
Test Procedure from the W3C Draft
Quoted from the provision's informative document, informative/guidelines/images-and-media/image-alternatives/image-alternatives-equivalent.md. It is the group's own procedure, not an editorial testing guide.
Procedure
For each text alternative:
- Check that the content of the text alternative is equivalent to the meaningful information in the image.
Expected results
- #1 is true.
W3C Working Group Status
The draft records no open editors' notes on this provision.
W3C Threads on This Provision
2 GitHub threads carrying 10 comments, fetched from w3c/wcag3 by the tracker. Titles, numbers and states are the threads' own.
⚠️ This summary is stale — comments landed after it was written.
What the Argument Is About
Whether "equivalent" is failing because the definition is too loose or because the existing requirement is simply not being tested and enforced properly.
Positions taken in the thread
In #370, argues alt text is a legacy of early image-loading problems rather than a disability-studies concept, and that in practice a filename like "dog32234.jpg" is treated as compliance. Cites Perkins at under 1 percent of the web compliant, AudioEye at around 3 percent and WebAIM's Million at 4 percent to argue the failure is systemic rather than incidental. Wants "equivalent" defined against the information-exchange literature and extended with guidance for describing people, maps, tables, charts and data visualisations, not just a title plus a one-sentence overview. Points at Instagram, where alt text is buried behind a hidden process and GenAI supplies descriptions like "Might be a man, wearing glasses".
patrickhlauke's opening reply is flat: "dog32234.jpg" would fail 1.1.1, so it is not legally compliant in any sense. TestPartners attributes the observed state to testers not testing the criterion correctly, automated tools being unable to judge appropriateness, and authoring platforms that do not help — a lack of education, not a defect in the wording, and something WCAG 3 cannot fix. yatil adds the structural point that W3C defines conformance and does not enforce it; enforcement runs through civil rights litigation and, in the EU, through the European Accessibility Act's reference to WCAG 2.1 via EN 301 549, with national agencies and fines that only began operating this year.
TestPartners identifies a newer failure mode: organisations now store images in a DAM with the text alternative attached to the asset, so the alternative is authored with no knowledge of the context it will appear in, and ends up an invariably literal description of image contents that may be appropriate in one placement and wrong in another. brett-oppegaard accepts the point, proposes that descriptions be crafted per use and logged so a forensic recontextualisation is possible, and concedes this would require a major shift in archiving practice. Both treat it as a real problem; neither claims it is the central one.
In #611, argues the draft never says which formats are usable for which medium and that the media alternative definition adds nothing. Offers an absurd-but-passing case: video-only content with an empty closed caption track satisfies the requirement as written. Proposes splitting the test procedure into separate procedures for audio-only, video-only and audio-video content, each ending in a check that the alternative is equivalent to the meaningful information in the media.
Agreed
- "dog32234.jpg" is not conformant under WCAG 2.x 1.1.1 — brett-oppegaard did not contest patrickhlauke's correction, and shifted to arguing about enforcement instead.
- Real-world conformance rates are very low; the disagreement is about the cause, not the number.
- W3C neither polices nor funds review of conformance claims; that sits with law, regulators and litigation.
Still open
- Whether WCAG 3 should tighten the definition of equivalent and add scaffolding, metrics and benchmarks — brett-oppegaard's core ask, which nobody in the thread endorsed or costed.
- What recourse exists against a false "this website is WCAG compliant" claim, and how many violations would invalidate it. brett-oppegaard asked directly; yatil answered only on the general enforcement landscape.
- Whether equivalence guidance should extend to specific content types — described people, maps, charts, data visualisations — beyond generic image alternatives.
- JasonAment's proposed per-medium test procedures in #611. kfranqueiro noted the upcoming Working Draft has separate provisions for transcripts, audio descriptions and captions, and lauracarlson posted an Image and Media Subgroup draft response saying the layered transcript architecture now addresses much of the ambiguity; JasonAment has not replied to it.
Note
Thin and lopsided. #370 is essentially brett-oppegaard against three respondents who all make the same rebuttal, and the exchange drifts from defining equivalence into enforcement and legal policy without returning. #611 is a concrete proposal that drew no debate; the only replies are kfranqueiro's pointer to the new separate provisions and the Image and Media Subgroup's draft response (posted by lauracarlson) saying the updated transcript framework addresses much of it.
WCAG 2.2 Criteria That Map Here
From this site's reviewed WCAG 2.2 → WCAG 3 map. The map is an interpretation, not a W3C mapping: W3C has not published one yet.
W3C Raw Source Text
Verbatim from guidelines/groups/images-and-media/image-alternatives/image-alternatives-equivalent.md · informative document: informative/guidelines/images-and-media/image-alternatives/image-alternatives-equivalent.md
Text alternatives for non-decorative images convey the equivalent purpose to the image.