Langues

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.

Built by Patrick Stox

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.

Feedback
Report a bug

Found something broken in Image Seo Checker? Let us know what happened — this goes straight to a private triage queue, not a public list.

What will be sent 
 No tool inputs, uploads, pasted source, complete results, query parameters, or URL fragments are attached automatically. You can edit or remove the selected passage above. Browser and anti-abuse metadata is processed for spam prevention. 
  
 
  
 
 
  
 
 
  
 
 
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.jpg has no alt attribute.
  • Observed: divider.svg has empty alt text, which may be correct for decoration.
  • Observed: chart.webp supplies descriptive alt text and dimensions.
  • Not evaluated: actual transfer sizes, rendered dimensions, and the page's LCP element.
 
 
 
How to use it
  1. Enter the public URL containing the images you want to review.
  2. Choose Audit images and inspect each evidence-backed raw-HTML check.
  3. Separate missing alt attributes from intentionally empty decorative alt text.
  4. Use a rendered performance test for any item this report marks not evaluated.
 
 
 
       
     
     
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 attribute, 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 LCP 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, accessibility, 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.
 
Next stepContent Gap Analyzer — look up the exact spec and expected values.

People also explore
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Feature requests for Image Seo Checker
 

Upvote what you want most. New ideas can be submitted from the floating Feedback menu;
      requests appear here once approved, and the most-wanted rise to the top.

   
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À propos de l’outil
Auditez les signaux d’image du HTML brut : attributs alt, chargement différé, priorité de récupération, formats source et balisage ImageObject.
Fonctionnalités
  • Couverture des attributs alt et images décoratives.
  • Indications sur le chargement de la première image et le LCP probable.
  • Détection des formats hérités et de la priorité de récupération.
  • Contrôle du balisage ImageObject sans exécuter le JavaScript de la page.
Fonctionnement
Le vérificateur récupère le HTML, inspecte les éléments img et leurs attributs, puis sépare les constats concrets des heuristiques de chargement et du signal ImageObject. Les résultats restent liés au document fourni et ne remplacent pas une mesure de terrain.
Limites
  • L’outil lit le HTML brut et ne voit pas les images ajoutées après le rendu JavaScript.
  • Le LCP probable est une heuristique ; confirmez l’élément réel avec des données de performance.
  • L’absence d’ImageObject est informative, pas automatiquement une erreur.
Questions fréquentes
L’attribut alt est-il obligatoire pour chaque image ?
Les images porteuses de sens doivent avoir un alt descriptif ; les images véritablement décoratives doivent utiliser un alt vide.
Le chargement différé est-il toujours mauvais pour le LCP ?
Non. Confirmez d’abord l’élément LCP réel et retirez le chargement différé seulement si cette image est responsable du LCP au-dessus de la ligne de flottaison.
Faut-il ajouter ImageObject à chaque image ?
Non. Ajoutez-le à une image principale lorsque ses informations structurées apportent une valeur claire, en gardant son URL et ses métadonnées exactes.