Image SEO Checker
Free, no signup. Audit image SEO signals visible in raw HTML. Rendered dimensions, real LCP, transfer sizes, and AI alt-text generation are shown honestly as unavailable in this tool.
Checks run from our server; we fetch the URL you enter and don't keep the results. Anonymous run-level outcome counters may be used for aggregate research; URLs, domains, IPs, and identifiers are never included, and no statistic is released below 100 runs.
Sample report
Illustrative example — based on the markup shown
<img src="hero.jpg">
<img src="divider.svg" alt="" loading="lazy">
<img src="chart.webp" alt="Quarterly traffic by channel" width="960" height="540">- Review:
hero.jpghas no alt attribute. - Observed:
divider.svghas empty alt text, which may be correct for decoration. - Observed:
chart.webpsupplies descriptive alt text and dimensions. - Not evaluated: actual transfer sizes, rendered dimensions, and the page's LCP element.
How to use it
- Enter the public URL containing the images you want to review.
- Choose Audit images and inspect each evidence-backed raw-HTML check.
- Separate missing alt attributes from intentionally empty decorative alt text.
- Use a rendered performance test for any item this report marks not evaluated.
Current target
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Local data
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- Rendered intrinsic-vs-displayed dimensions and actual LCP element require a render budget.
- Transfer-size checks require asset requests.
- AI alt-text generation is not enabled in this tool.
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What the results mean
A finding reflects only markup visible in the response. Missing attributes and clearly unsupported patterns require attention; observations such as empty alt text need human context. A pass confirms one implemented rule, while not evaluated explicitly means the tool did not request or render enough evidence.
How it works
The checker fetches the public page and parses its raw HTML into a document context. Image-category detectors inspect supported img attributes and ImageObject markup, then return structured severity, summary, and evidence fields. It does not request the image files themselves.
Features
- Alt-attribute coverage and image-markup checks.
- Loading hints, format clues, and supported ImageObject signals.
- Evidence from the page source without uploading image assets.
- Explicit not-evaluated output for render- and network-dependent checks.
Limitations
The tool cannot see CSS backgrounds, canvas content, JavaScript-injected images, visual image meaning, file bytes, compression quality, rendered display size, or real performance timing. It cannot write alt text responsibly without seeing and understanding the image in context.
Frequently asked questions
Should every image have descriptive alt text?
Every img element should have an alt attributeAlt text is the value of the `alt` attribute on an HTML `<img>` element — a short text substitute chosen for the image's purpose and context, not a literal description of what it shows. It makes images accessible to screen-reader users and helps search engines understand images, mainly for image search., but decorative images should usually use an empty alt value. Informative images need concise text that conveys their purpose in context.
Can this tool identify the Largest Contentful Paint image?
No. Actual LCPLargest Contentful Paint — render time of the largest visible image or text block, relative to when the page started loading. ≤2.5 s (at the 75th percentile) is good. requires a rendered performance measurement. This checker reports that check as not evaluated rather than guessing from source order or filename.
Does WebP automatically improve image SEO?
No. A modern format can reduce transfer size, but search visibility also depends on relevance, accessibilityWeb accessibility means designing sites so people with disabilities can use them, per the W3C's WCAG guidelines. It overlaps with SEO in specific, checkable ways — alt text, heading structure, descriptive link text, captions, and page speed all serve both audiences — but Google has said accessibility itself is not a ranking factor, and most WCAG success criteria (keyboard focus order, ARIA live regions, form labels) have no SEO effect at all., discoverability, surrounding text, and correct page implementation.
Why are CSS background images missing?
The checker reads image signals in raw HTML. It does not fetch stylesheets or render CSS, so background images and JavaScript-inserted images are outside its evidence set.
Feature requests for Image Seo Checker
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Common issues & how to fix them
- Warning Image lacks an alt attribute Fix: Add concise alt text that communicates each meaningful image’s purpose, and use empty alt attributes for decorative images.
- Warning First image is lazy-loaded and may be LCP Fix: Confirm the actual LCP element first, then remove lazy loading from the above-the-fold LCP image if this image is responsible.
- Information Likely-LCP image lacks high fetch priority Fix: Add fetchpriority=high only if performance testing confirms the first image is the above-the-fold LCP image.
- Information Image uses a legacy source format Fix: Compare transfer size and quality, then serve an AVIF or WebP source with a compatible fallback when it materially reduces bytes.
- Information ImageObject markup is absent Fix: Add ImageObject only for a primary image that benefits from structured description, and keep its URL and metadata accurate.