Synthetic teaching example for a website delivery brief. Not a client result, live account test or certification.
The same asset can need three different alternatives
For a design studio’s new portfolio, ask what a visitor must learn or do from each image. An informative drawing, a decorative repetition and an image-only link are not interchangeable. Writing the same keyword-rich sentence for all three can hide the actual purpose.
| Use | Useful alternative | Why |
|---|---|---|
| Informative plan | Fictional concept plan with studio at left, meeting room at right and entry below. | Describes the supplied diagram, not imagined finishes |
| Image repeats adjacent equivalent explanation | Empty alt, when genuinely redundant | Avoids repeating the same information |
| Image-only link | View the fictional studio concept | Communicates the link purpose |
Use the filled example
Download the finite Node checker and filled input. Run with Node 24 or newer; no account, API or network is used.
node checks.mjs portfolio-alt-context portfolio-alt-context.jsonThe filled input names the actual labels STUDIO, MEETING and ENTRY in the supplied SVG. The checker produces context-specific draft alternatives; it does not infer image meaning. Compare each sentence with the actual diagram and surrounding text. An empty alternative is inappropriate if that removes unique information, while a destination label alone is inadequate if important diagram information otherwise disappears.
Acceptance evidence to request
Have the editor demonstrate the three real contexts in the content system. Inspect the accessible name of the link, reading order and whether a nearby caption already provides the same description. For a complex plan, keep the concise alternative and provide the essential relationships in ordinary nearby text. Do not invent measurements or engineering claims that are absent from the drawing.
The asset deliberately contains only three spaces and no real address. This exercise does not certify WCAG conformance or validate every screen reader. A human must review the final content context, keyboard interaction and the actual delivered accessibility tree. No existing portfolio image, alt attribute or homepage artwork is changed by this guide.
Primary facts and limits
W3C image alternative decision tree: Alternative text depends on image purpose, redundancy and link function.
Sources reviewed 15 October 2026. The supplied input and acceptance rules are original teaching design; check current platform versions and your actual delivery contract before implementation.