The test is whether removing the image loses information
Aliases: removal test · decorative vs informative · images off
What it is
Whether an image is decoration does not follow from stock-photo status, size, or brand taste. The operational test: after it is gone, would a first-time visitor lose a fact or an action. If yes, it is informative and needs alternative text. If no, it is decoration and should be hidden from assistive technology. If a neighboring sentence already says the same thing, removing the image loses nothing — treat it as decoration so it is not announced twice.
Why it happens
Designers classify by genre: “illustration means decoration,” “product shot means information.” Genre is not information. The same handshake photo can be removed from an about page without touching any proposition, and cannot be removed from a “signing-day” report without losing who was in the room. Visual weight, mood, and brand atmosphere can be real for sighted users and still not be facts that must enter the speech stream. The removal test asks about propositions and actions, not about whether it looks good.
The test has to be run in the task, not against a component library. An icon removed from a button with no visible words loses a comprehensible control; the same icon beside the word “Download” loses nothing. Complex figures almost always fail removal, which means they need an alternative channel, not the caption “diagram.”
Studying it
Turn images off in the browser, or paint them out on a screenshot, and ask someone new to finish the task and restate the points. Compare success and missed facts with versus without the image.
Independent variables: whether adjacent copy already contains the same proposition, whether the task depends on a detail inside the image. Dependent variables: task failure with images off, count of missed facts, informative images mislabeled as decoration.
Log “author thinks it is decoration” separately from the removal result. Disagreements are the review queue.
Where it stops holding
CAPTCHAs, signatures, and challenges that must be seen fail removal by construction and cannot be marked decorative. A mood hero that loses atmosphere but no proposition is usually still decoration. An icon that is the only label fails removal and is information. If a neighboring paragraph already states everything the figure adds, removal keeps the propositions; name it briefly or hide it rather than repeating a third time.
Applying it
- On every image, do a five-second removal: paint it out, ask whether the sentence or the action remains.
- If it remains: hide as decoration, or confirm the visible words already are the name.
- If it does not: write functional or informational alternative text; if relationships are dense, mark that a long description is required.
- Verify: disable image display and walk the main path. Any step that cannot be done, or fact that cannot be stated, belongs to an image that is not decoration. When the author says “it is just nice” and the test fails, keep the test.