Alt Text Checker: Find Every Image Missing Alt Text

Here's the mismatch I see constantly in client emails: someone asks "how do I check alt text on my whole site," and the answer they find online is "right-click an image, choose Inspect, look for the alt attribute." That works. For one image. If your site has sixty images and you've been asked (by a client, a Lighthouse warning, or an accessibility complaint) to check all of them, right-clicking sixty times is not a plan, it's a punishment.

This is where an alt text checker earns its keep. Instead of inspecting one image at a time, you paste a page URL and get every image on that page back with a verdict: does it have alt text, is that alt text actually useful, or is something missing entirely. Below, I'll walk through the fast single-image method first (sometimes that really is all you need), then the whole-page method, then what to do with the results.

How Do I See the Alt Text of an Image?

Alt text (short for "alternative text") is the words stored inside an image's HTML code that describe what the image shows. A screen reader announces it instead of the picture, a browser displays it if the image fails to load, and search engines read it to understand what the image is about, which is also why Google's own image SEO best practices treat a genuine description as far more useful for Google Images than a filename or a keyword-stuffed phrase. It lives inside the alt attribute of an <img> tag, something like <img src="dog.jpg" alt="Golden retriever puppy chewing a shoe">.

If you want to check just one image, here's the fastest route:

1. Right-click directly on the image in your browser and choose "Inspect" (Chrome, Edge) or "Inspect Element" (Firefox). You should see a panel open, usually at the bottom or side of your browser window, with the page's HTML code highlighted. If nothing opens, you likely right-clicked slightly off the image; try again, aiming for the visible picture itself rather than the space around it.
2. Look at the highlighted line. It should show an <img> tag with several attributes inside it (things like src, width, class). If you see alt="some text here", that's your alt text. If you see alt="" with nothing between the quotes, the image has been deliberately marked as decorative, which is a valid choice, not an error, for purely visual images. If there's no alt attribute at all in the tag, that image has no alt text, and that's the actual problem worth fixing.
3. If the highlighted code shows a different tag entirely, like a <div> or <picture> wrapping the image, scroll slightly in the inspector panel; the <img> tag is usually nested one level in. Click the small triangle or arrow next to the wrapping tag to expand it.

You can also skip DevTools entirely: right-click anywhere on the page (not on an image) and choose "View Page Source," then press Ctrl+F (Cmd+F on a Mac) and search for alt=. This jumps you straight to every alt attribute on the page, one by one. It's a fine trick for a quick spot check, but it stops being fine once you have more than a handful of images, because you're still reading each result yourself with no summary of how many are missing, empty, or just a filename.

Is there a Chrome extension to view alt text?

Yes. Several browser extensions in Chrome's Web Store exist specifically to show alt text without opening DevTools: hover over an image and a tooltip displays its alt attribute, or the extension outlines images that have no alt text at all so they're visible at a glance. This article won't name a specific one, since extensions change hands, permissions, and quality fairly often, and a recommendation could point you toward something abandoned by the time you read this.

What's worth knowing instead is the trade-off. A browser extension needs to be installed per machine, and it only shows what's on the page currently loaded in that tab, so you still need to click through every page one at a time. A URL-based checker skips both problems: no install, and you can audit a page from any device the moment you have its address.

How do I find all images missing alt text on my site, fast?

This is the part most guides skip. Here's how to run a real alt text audit on an entire page in one pass, using imagecheck.tools, a free checker that reads a page's images and hands back a verdict for each one instead of a single missing-or-present flag.

What you'll need: the live URL of the page you want to check (or its raw HTML, if it isn't public yet), and about two minutes. No account, no login, no install.

1. Open the free alt text checker in your browser. You should see two tabs near the top of the page: "Check a URL" and "Paste HTML." If the page looks blank, refresh once; this occasionally happens on a slow connection.
2. If your page is live, stay on the "Check a URL" tab and paste the full page address, including https://. If the page is still in development, staging, or password-protected, switch to "Paste HTML" instead and paste the page's source code (View Page Source, then select all and copy). Paste mode keeps everything in your browser.
3. Click the check button and wait. You should land on a results page within a few seconds showing a score, a summary line, and a scrollable list of every image found. If you see an error about the page being unreachable (an HTTP status code other than 200), double-check the URL for typos and confirm the page isn't blocked by a login wall.
4. Scroll to the Images section. Each row shows a thumbnail (in URL mode), a verdict chip, any flags, and the alt text found, if any. This is your whole-page audit in one screen instead of one image at a time (the same report also grades file weight, which our guide on reducing image file size explains how to fix). If the list looks short, remember the tool probes up to 40 image files per check; on a much larger page, focus this pass on the images above the fold first.
5. Read the verdict chips, not just the alt text column. A chip that says "missing" needs attention now. A chip that says "filename" or "generic" means alt text exists but isn't doing its job. A chip that says "decorative" with an empty alt attribute is very likely fine, and I'll explain why in the next section.

What each verdict means (an alt text audit at a glance)

A verdict chip is only useful if you know what it's telling you to do next. Here's the plain-language version of each one, ordered from what usually needs fixing first to what usually doesn't.

This table lines up with how the W3C Web Accessibility Initiative's own alt-text decision tree separates images into three outcomes: empty alt for decorative images, descriptive alt for images that carry meaning, and functional alt for images that sit inside links or buttons, where the text should describe the destination or action rather than the picture. Worth a look if you want the source logic straight from the standards body: the W3C WAI decision tree.

Does empty alt count as missing?

No, and this is the single most common mix-up I see in comments and support emails. alt="" and no alt attribute look almost identical if you're skimming code quickly, but they mean opposite things. An empty alt attribute is a deliberate, correct choice for images that add nothing informative: a decorative border graphic, a repeated icon next to text that already says the same thing.

A missing alt attribute is an oversight, and MDN's img element reference notes that assistive technology treats the two differently: some screen readers fall back to announcing the filename or file path when the attribute is absent entirely, which is exactly the confusing experience alt text exists to prevent.

On imagecheck.tools, this distinction is built into the verdicts themselves: "decorative" means alt="" was found and treated as correct, while "missing" means the attribute wasn't there at all. If you're scanning a report and see a decorative chip, that's not a failure waiting to be fixed. It's the tool confirming the image was handled the way accessibility guidance recommends. This lines up with the requirement in WCAG 2.2's Success Criterion 1.1.1, which asks for a text alternative that serves an equivalent purpose, not text on every single image regardless of whether it carries meaning; read the full criterion at W3C's Understanding Non-text Content page.

What this check can't tell you

An alt text checker, including this one, is mechanical. It can tell you an alt attribute exists, that it isn't a bare filename, and that it isn't just the word "image" typed in to satisfy a form field. It cannot tell you whether the description is actually true. If a photo shows your storefront on a rainy Tuesday and the alt text says "sunny beach vacation," only a human glancing at both the picture and the words can catch that.

It also doesn't run any JavaScript, so images inserted dynamically after the page loads may not show up in the results, and the report caps out at 40 probed image files per check, so an image-heavy landing page might need a second pass. The full list of what the report grades and its stated limits is on the imagecheck.tools about page.

None of that makes the check useless, treat it the way you'd treat a smoke detector rather than a fire inspector: it tells you where to look, it doesn't replace looking.

Which verdicts to fix first

If your report comes back with a long list and you're not sure where to start, work in this order:

1. Missing and empty-link images first. These break navigation and comprehension for screen reader users right now, especially empty-link images, since a link with no accessible name gets announced as nothing more than "link" or a raw web address. The WebAIM Million report, an annual analysis of the top one million home pages, found that 45% of images missing alt text were sitting inside links exactly like this, so it's a common gap, not an edge case.
2. Filename and generic verdicts next. These are quick wins because the image already exists on the page and someone already opened the upload dialog for it; writing one real sentence of description takes a minute or two per image. The same WebAIM report found that 10.8% of images with alt text present still carried "questionable or repetitive" text of exactly this kind.
3. Decorative confirmations last. Spot-check a handful to make sure they really are purely visual, then move on.

For guidance on what to actually write once you've found a problem image, our alt text writing guide covers the specifics by image type: product photos, charts, logos, icons, and images sitting inside buttons or links. This article is about finding the gaps; that one is about closing them.

Alt text is only one piece of getting images to perform well in search, alongside file names, dimensions, and how Google actually discovers a page's images; our image SEO guide covers the rest of that picture if you want to go beyond accessibility into Google Images visibility too.

One more number worth holding onto: across that same WebAIM sample, 53.1% of home pages had at least one image missing alt text somewhere on the page. That's the share of pages with a problem, not the share of images (the actual image-level figure is 16.2%, roughly 1 in 6 images sampled). Keep those two numbers separate; conflating them makes the scale of the problem sound either much smaller or much larger than it actually is.

Frequently Asked Questions

How do I see the alt text of an image?

Right-click the image in your browser and choose "Inspect" (or "Inspect Element" in Firefox), then look inside the highlighted <img> tag for an alt="..." attribute. Alternatively, right-click the page itself, choose "View Page Source," and search for alt= with Ctrl+F or Cmd+F. Both methods work well for checking a single image but don't scale past a handful, since you're reading each result manually with no summary of how many images have a problem.

How do I find all images missing alt text on my site?

Paste the page's URL into an alt text checker like imagecheck.tools and run the check; the report returns every image on that page in one scrollable list, each with a verdict chip such as "missing," "decorative," "filename," or "ok," so you can see the whole picture instead of inspecting images one at a time. For a page that isn't live yet, use the tool's paste-HTML mode instead of the URL mode, since nothing needs to be publicly reachable for that to work.

Is there a Chrome extension to view alt text?

Yes, several extensions on the Chrome Web Store show an image's alt text on hover or highlight images that have none. They need to be installed per browser and only show results for the page currently open in that tab, so checking a whole site still means clicking through every page yourself. A URL-based checker skips the install step entirely and can audit a page from any device.

Does empty alt count as missing?

No. An empty alt attribute (alt="") is a deliberate marker that an image is purely decorative and has nothing to announce, which is correct for many background and spacer images. A genuinely missing alt attribute means the attribute wasn't written into the code at all, and some screen readers respond to that by announcing the filename instead, which is the real accessibility gap worth fixing.