Alt text checker
Finds images, icons and image buttons with missing or empty text alternatives, and alt text that says nothing useful.
What this check looks for
The audit runs this check with every other check, on the page as the browser renders it.
- Missing alt attributes
- Images with no alt attribute, so screen readers read the file name or skip the image.
- Empty image buttons and links
- Linked images and image buttons with no text, so the control has no name.
- Placeholder alt text
- Text such as "image", "photo", "banner" or a file name that tells a listener nothing.
- Images of text
- Pictures of words that should be real text, flagged for a person to confirm.
What a failure looks like
The hero photo on a clinic home page has no alt attribute. A screen reader announces the file name instead.
<!-- Broken: no text alternative -->
<img src="/images/reception-2024-final.jpg" class="hero__photo"><!-- Fixed: describes what the photo shows -->
<img src="/images/reception-2024-final.jpg" class="hero__photo"
alt="Bright reception area with a wooden front desk and two chairs">
<!-- Fixed: decorative images get an empty alt -->
<img src="/images/divider.svg" alt="">How it shows in AccessGuard
Each finding names the WCAG criterion, explains the problem in plain words and shows the element that fails, so a developer can find it on the page.
WCAG criteria
Findings from this check name one of these criteria. How much of each the audit can decide on its own:
| Criterion | Level | Automation |
|---|---|---|
| 1.1.1 Non-text Content Missing alt text is found automatically. Whether the text describes the image well needs a person. | A | Partly automated |
| 1.4.5 Images of Text | AA | Partly automated |
What still needs a person
No automated tool can confirm these. AccessGuard marks related findings as Review, so nobody mistakes them for a pass.
- Whether the alt text describes what matters about the image in its context.
- Whether an image is decorative and should have empty alt text.
- Complex images such as charts and maps that need a longer description.
Questions
Does every image need alt text?
Every img element needs an alt attribute. Images that carry information need text that describes them. Purely decorative images should use an empty alt attribute (alt="") so screen readers skip them.
Can an automated check tell whether alt text is good?
It can find missing alt text and obvious placeholders such as file names. Whether the text describes the image well in its context needs a person to judge, so AccessGuard marks those cases for review.
How long should alt text be?
As short as it can be while still saying what the image contributes to the page. A sentence is usually enough. Charts and diagrams need a longer description elsewhere on the page.
Related checks and guides
- Link text checker
Finds links with no accessible name, vague text like "click here", and links that open new windows without warning.
- Form labels checker
Finds inputs without labels, placeholders used as the only label, and fields that don't say what they collect.
- ARIA checker
Finds invalid roles and attributes, controls with no accessible name and ARIA that hides content people need.
- How to Write Alt Text: Image Description Rules + Examples
Guide
- Most Common WCAG Violations (With Code Fixes for Each)
Guide
Check a client page for alt text issues
The free audit runs this check and every other one. Results in about a minute.