G94Sufficient technique WCAG 1.1.1 Level A Human testing required

Write alt text that serves the same purpose as the image

Having alt text is not the goal. Doing the image's job is. G94 sets that as a substitution test, so you take the image away, put the text in its place, and check that no information and no function went missing. W3C's own example is the search button drawn as a magnifying glass, whose alternative is search rather than magnifying glass, because the button's job is the search and not the drawing. W3C also gives four questions for working out what to write. Why is the image here, what information does it present, what job does it do, and if you could not show it at all, what would you say instead? There is a wrinkle in how this one is filed. W3C counts G94 as sufficient for 1.1.1 Non-text Content only when a more specific technique carries it, H37 for an img element or H36 for an image submit button. So G94 is the standard the words get judged against, not the markup that passes the rule. And where a sentence cannot hold everything, W3C's answer is a brief overview in the alt with a long description alongside, not a paragraph crammed into an attribute.

How we find it in an audit

No scanner makes this judgment, and this is one of the few pages in the library where we say that flatly. A tool accepts alt="photo" and moves on. Our reviewers run the substitution test by hand on every image that carries meaning, covering the picture and reading what is left of the page. Every alt that leaves the sentence poorer than it was gets flagged. Charts and diagrams take the longest, because that is where a short alternative usually needs a long description behind it.

How affected users experience it

Bad alt text is often worse than none, because it costs the same listening time and delivers nothing. Banner final two is a string the listener has to hear, decode and throw away. Good alt text is invisible. The information simply arrives, and on a chart that is the whole difference between hearing that revenue doubled and hearing the word chart.

Passes vs. fails

Passes: alt text names the product. Fails: the file name is all there is.

Passes

<img src="q4.png" alt="Line chart. Revenue doubled from $2M to $4M during 2025.">
<button><img src="search.svg" alt="Search"></button>

Fails

<img src="q4.png" alt="chart">
<button><img src="search.svg" alt="magnifying glass"></button>

How this gets tested

The W3C publishes test rules that define what a checker looks for here.

Element marked as decorative is not exposedA tool can check this
Image accessible name is descriptiveA tool finds candidates, you decide
Image button has non-empty accessible nameA tool can check this
Image has non-empty accessible nameA tool can check this
Link has non-empty accessible nameA tool can check this
Object element rendering non-text content has non-empty accessible nameA tool can check this
SVG element with explicit role has non-empty accessible nameA tool can check this
Image not in the accessibility tree is decorativeA tool can check this

Other ways to satisfy this rule

39 guides on this site are filed under 1.1.1 Non-text Content. W3C lists this one as sufficient for that rule when it is implemented through a more specific technique, so the condition is part of the test rather than a footnote to it.

This guide is our interpretation of W3C technique G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.