Image alt text checker

What is the image alt text checker?

The image alt text checker is a page-auditing tool that takes a page URL, retrieves the page, and scans every image on it to find the ones that are missing alt text. You enter a URL into the form and submit it. The server fetches the page, collects the image elements, and checks each one for an alt attribute, returning a report of the images that have no usable alternative text.

Alt text is the short description attached to an image that explains what the image shows. It matters for three audiences at once: visitors using screen readers, search engines that cannot see the image itself, and people on slow connections where images fail to load. When alt text is missing, all three lose information, which makes checking for gaps a basic but essential part of on-page quality.

Because alt text lives in the markup rather than in the image file, it is easy to lose silently. An image can be uploaded, moved, re-exported, or replaced without its description surviving the trip, and no one notices until a screen reader reads a blank label or a search engine tries to make sense of an image it cannot see. Checking a page surfaces those quiet gaps.

The check is deliberately narrow, and that narrowness makes it trustworthy. It does not judge whether your alt text is good or guess at what an image shows; it simply reports which images have no text to work with. A precise, verifiable list of gaps is more useful for getting fixes done than a vague quality score, because every item on it maps to a concrete edit.

Adding alt text is also cheap relative to its payoff. Each fix is a short descriptive string typed into a content field or a template, and the benefit applies immediately to everyone who encounters the page: screen reader users get the description, search engines get context for the image, and readers on flaky connections see meaning instead of a broken block. The checker simply makes sure the cheap fix is actually applied everywhere.

What the image alt text checker finds

When you submit a URL, the tool fetches the page and looks at every image element in the document. For each one it checks whether an alt attribute is present and whether that attribute actually contains text. An image with no alt attribute at all is flagged, and so is an image whose alt attribute exists but is empty, since an empty attribute provides nothing for a screen reader to announce or a crawler to read.

The report collects the flagged images together so you can see the scope of the problem at once. Each entry shows the image that is affected, which lets you map the finding back to a specific spot on the page and decide what the alt text should say. Seeing the list as a whole also reveals patterns, such as a content block whose images were all uploaded without descriptions, or decorative images that were left without any handling.

It is worth noting that a missing alt attribute and an empty alt attribute are not always the same problem. An empty alt attribute is a legitimate choice for purely decorative images, because it tells assistive technology to skip them. A completely missing attribute is usually a mistake, since it leaves the image unlabeled entirely. The checker surfaces both conditions so you can tell them apart instead of treating every flagged image the same way.

Distinguishing the two matters for how you respond to the report. A flagged decorative image with an empty attribute may need no change at all, while a flagged image with no attribute probably does. Working through the list with that distinction in mind turns the audit into a series of quick decisions rather than a uniform habit of adding text everywhere.

How to use the image alt text checker

Finding the images that need attention on a page is a short workflow of submitting the URL and reading the flagged list.

1. Copy the full URL of the page whose images you want to audit.
2. Open the image alt text checker page and paste the URL into the form field.
3. Submit the form so the server fetches the page and checks the alt attributes of every image on it.
4. Review the returned list of images that are missing alt text, matching each entry to the image it refers to on the page.
5. Write a concise, descriptive alt attribute for each meaningful image, leaving decorative images empty, then re-check the page.

How to get better results

• Describe what the image actually shows, using the surrounding text as context. Good alt text fills the gap a reader would have without the image.
• Keep alt text concise. A full sentence or two that captures the meaning beats a long paragraph, and it stays useful in every context where the text is read aloud.
• Decide consciously about decorative images. Images that add no information should have an empty alt attribute, not a missing one, so they are correctly skipped.
• Avoid stuffing alt text with keywords. The text exists to describe the image, and describing it naturally serves both readers and search engines better.
• Re-check the page after every image change. New uploads, template edits, and CMS migrations routinely drop alt attributes that were previously in place.
• Scan multiple key pages rather than one. If a template or a batch upload is the culprit, the same missing alt text will repeat across every affected page.

Why the image alt text checker matters

Alt text is one of those on-page details that is invisible until it is missing. A visitor with a screen reader, a search engine indexer, or a reader on a broken connection each depend on it differently, and none of them can recover what the image would have shown. Finding the gaps before those audiences hit the page is a straightforward quality improvement with a real effect on accessibility and on how well the page's images are understood.

The checker matters because image problems scale silently. One unlabeled image on one page is easy to overlook, but the same missing attribute repeated across a gallery, a blog archive, or a product range becomes a substantial body of inaccessible content. A tool that lists the offending images turns that hidden scale into a concrete list of fixes, making the clean-up a mechanical task rather than a search.

There is a practical payoff for compliance and quality scanning too. Accessibility requirements and internal quality standards both care about alt text, and a documented audit gives you a defensible record of which images were checked, when, and what was found. That record is exactly what a reviewer, client, or auditor asks for when accessibility comes up.

Finally, the check is an easy way to set a baseline and track improvement. Run it once to see how many images are unlabeled, fix the gaps, and run it again to confirm the page is clean. Keeping that before-and-after view makes the effort tangible and gives everyone involved a clear number to point to.

When to use the image alt text checker

The best time to check alt text is before the images after it are relied on, and the best times after that are whenever content changes. Here are the situations where the check earns its keep.

• When a page has been published with a batch of new images and you want to confirm every one of them has alt text.
• When you are improving accessibility on your site and need a page-by-page list of the images that are currently unlabeled.
• When images have been migrated, moved, or re-uploaded and you suspect their alt attributes did not survive the process.
• When a page depends on images being understood by search engines and you want to verify each one is described.

Frequently asked questions

What counts as missing alt text in the checker's report?

An image is flagged when it has no alt attribute at all, or when the alt attribute exists but contains no text. Both conditions leave the image without usable alternative text for screen readers and crawlers.

Is an empty alt attribute always a problem?

No. For purely decorative images, an intentionally empty alt attribute is the correct markup because it tells assistive technology to skip the image. The checker reports empty attributes so you can confirm each one is a deliberate choice.

Does the tool check images loaded from other domains?

It scans the images that appear on the page you submit, including images referenced from other domains, and reports the ones that are missing alt text regardless of where the file is hosted.

What should I write in alt text?

Write a concise description of what the image shows that adds information the surrounding text does not. The right description depends on the image's role on the page, which is why the checker pairs each finding with the image that needs it.

Will the checker fix the images it finds?

No. It finds the images that are missing alt text and lists them so you know what needs attention. Adding the descriptions is an edit you make in your content or CMS, after which you can re-check the page.