Image alt text for SEO and accessibility — when empty alt is correct

Quick frame: Alt text serves two audiences — screen readers and image search. Decorative images should have empty alt (alt=""). Content images should have descriptive alt (5–15 words). Missing alt is always wrong; empty alt is sometimes right.

The three states

State	HTML	When
Missing	<img src="...">	Never correct
Empty	<img src="..." alt="">	Decorative images
Descriptive	<img src="..." alt="Family at Marina Beach">	Content images

Use the image alt checker to audit your HTML.

Empty alt for decorative images

Decorative images that add no information:

• Spacer / divider graphics.
• Background patterns rendered as img.
• Decorative icons paired with a text label ("❤️ Like" — the heart needs no alt).
• Stock photos chosen for visual interest only.

Empty alt tells screen readers to skip. Missing alt (no attribute at all) makes screen readers read the filename — almost never useful.

Descriptive alt for content images

Content images carry meaning. Examples:

• Hero photos that illustrate the article's topic.
• Charts, graphs, infographics — describe the data, not just the visual.
• Product photos — describe the product (model, colour, key feature).
• Diagrams — describe what's being shown.

Aim for 5–15 words. Screen readers cut off around 125 characters.

Functional images (buttons, links)

When an image is the only content of a link or button, the alt becomes the link's effective anchor text. Describe the action:

<a href="/cart">
  <img src="/cart-icon.svg" alt="View cart">
</a>

Not "Cart icon" — that describes the image. "View cart" describes the action.

SEO bonus

Alt text is a primary signal for Google Image Search. A well-optimised alt can earn position in image SERPs and feed AI Overview image citations. But — write for accessibility first; SEO is the side benefit.

Common mistakes

• "Image of..." or "Picture of..." — screen readers already announce "image". Don't repeat.
• Keyword stuffing alt text with the target keyword.
• Copy-pasting the same alt across many images.
• Forgetting alt on hero / banner images entirely.

Audit checklist

1. Run image alt checker on each major page.
2. Resolve all "missing alt" cases — add alt (empty or descriptive).
3. Spot-check decorative images use empty alt, not missing.
4. Spot-check content images have meaningful alt under 125 chars.
5. Re-audit after every CMS upgrade — alt attributes sometimes get stripped.

The wider on-page hygiene checklist is in heading hierarchy H1, H2, H3 rules.

FAQ

Q. Does Google still rank images without alt? A. Yes — Google uses surrounding text and filename as fallbacks. Alt is strongest signal but not strictly required.

Q. Should alt text include the brand or site name? A. Only if the brand is naturally part of the image (logo, product packaging). Don't append "by Brand" gratuitously.

Q. What about decorative SVG icons inside buttons? A. The button already has its own accessible name. Use aria-hidden="true" on the SVG (and empty alt if it's rendered as img).