axe-core input-image-alt error image button missing alt text

axe-core input-image-alt error image button missing alt text - how to fix it

TL;DR

An [input type="image"] is a submit button rendered as a picture, so it needs alt text the same way a text button needs a label. Add alt="Search" (or whatever the button does). If the image is purely decorative and the form already submits another way, replace the image input with a real [button] instead of leaving an unlabeled image button in place.

This rule is critical severity, which means it fails most CI accessibility gates immediately. Because [input type="image"] is rare in modern code, the violation usually lives in legacy templates, CMS themes, or generated pagination. Search the whole template directory for type="image" rather than fixing only the flagged page; the same snippet is almost certainly reused.

The verbatim error looks like this:

axe-core 4.x
Rule: input-image-alt (critical)
"Image buttons must have alternate text"

Element: [input type="image" src="/img/go.png"]
  Missing alt attribute.

Steps

1. Reproduce with the single rule:

npx @axe-core/cli https://example.com/checkout --rules input-image-alt

Expected: each [input type="image"] without alt is listed.

2. Open the flagged markup and confirm the element is genuinely an image submit button and not a decorative image that happens to sit inside a form.
3. Add concise alt text describing the action, not the picture:

[input type="image" src="/img/go.png" alt="Place order"]

'Place order' beats 'green arrow button' because the alt text is the button's name.

4. Re-run the focused scan. Expected output: 0 violations for input-image-alt.
5. Check that the same form does not have sibling button-name violations on other submit controls:

npx @axe-core/cli https://example.com/checkout --rules input-image-alt,button-name

6. Search all templates for the pattern, since image inputs are usually in shared partials:

rg -l 'type="image"' templates/ themes/ src/

Fix every occurrence, not just the one the scan found.

7. Consider replacing the image input with a [button] containing an [img] with alt text, which is easier to style responsively and supports SVG:

[button type="submit"]
  [img src="/img/go.png" alt=""]
  [span]Place order[/span]
[/button]

Here the visible text is the name and the decorative image gets empty alt.

When to use

• Axe flags input-image-alt on [input type="image"] elements.
• A legacy form uses image submit buttons with no alt text.
• An audit lists 'image buttons must have alternate text' as a critical violation.

When not to use

• The element is a decorative [img] (that is image-alt territory).
• The control is an [svg] inside a [button] (that is svg-img-alt / button-name territory).
• The image button is decorative and redundant: replace it with a text button rather than writing alt text for decoration.

Why it happens

[input type="image"] submits the form when activated, so assistive tech announces it as a button. With no alt attribute, the accessible name is empty and the user hears 'button' with no idea what it does. Because the rule is critical severity, it is also one of the violations most likely to fail an automated CI gate.

[input type="image"] dates to the early web, when it was the only way to make a graphical submit button. Modern CSS made it obsolete, but old themes and form builders still emit it. Because sighted testers see a perfectly clear button, the missing name is invisible without a scan, and because the element is uncommon, developers do not recognize the axe message when it appears.

Edge cases

• Image buttons with alt="" (empty alt) still fail. An image input is never decorative in the accessibility tree; it always needs a name.
• If the alt text duplicates nearby visible text ('Go' next to a visible 'Go' label), keep it short but keep it present.
• Some old CMS themes render image inputs for pagination arrows. Give each a functional name like 'Next page' and 'Previous page'.
• Server-side image maps ([input type="image"] with usemap) are a separate, worse problem; the server-side-image-map rule flags those. Prefer a plain image button or real links.
• Some bots and scrapers treat image inputs specially (they submit x/y coordinates). Replacing with [button] changes the submitted payload; check server-side handling before swapping.
• If the image fails to load, the alt text renders as the button label. Keep alt short so the broken-image fallback stays usable.
• High-DPI displays need srcset on [img]; [input type="image"] has no srcset support, another reason to prefer the button pattern.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_4j438B651jbnHAdYHqIUSQ