Free Image SEO Checker
Find images missing alt text and dimensions.
What is the Image SEO Checker?
Images are often a page's heaviest content and its biggest missed SEO opportunity. An image with no alt text is invisible to search engines and screen readers; an image with no width and height shoves your layout around as it loads, hurting Core Web Vitals and the user experience.
This image SEO checker fetches any URL and audits every image for the details that matter — alt text, dimensions and lazy-loading.
Last updated: Aug 13, 2026
What does this tool do?
You enter a URL and the tool fetches the page and reads every <img> element and its attributes.
It reports which images are missing alt text, which have empty alt, which lack width and height, and which don't lazy-load — with guidance on each.
Key features
Alt-text audit
Separates missing, empty and present alt text.
Dimension check
Flags images without width/height (layout shift).
Lazy-loading
Shows which images defer loading.
Per-image list
See each image with its status badges.
Problem-first
Images needing attention are listed first.
Example
Common use cases
- SEO specialists — Improve image-search visibility with alt text.
- Accessibility reviewers — Find images that fail screen readers.
- Developers — Add width/height to prevent layout shift.
- Content editors — Catch images uploaded without alt text.
- E-commerce owners — Ensure product images are described.
- Performance engineers — Spot images that should lazy-load.
- Agencies — Audit a client's image hygiene.
- Bloggers — Keep post images accessible and indexable.
Benefits
- It finds missing alt text that hurts SEO and accessibility.
- It flags images that cause layout shift.
- It shows where lazy-loading could speed up the page.
- It lists the problem images first so fixes are fast.
Tips
- Write descriptive alt text for meaningful images; leave alt="" only for decorative ones.
- Always set width and height (or an aspect-ratio) to prevent layout shift.
- Add loading="lazy" to below-the-fold images.
- Describe the image, don't stuff keywords, in alt text.
- Use modern formats like WebP or AVIF to cut file size.
- Give images descriptive file names before uploading.
- Serve responsive sizes with srcset for different screens.
- Re-check after adding a gallery or new image-heavy page.
Common mistakes to avoid
Missing alt text
Fix: Add concise, descriptive alt text to every meaningful image.
No width/height
Fix: Set explicit dimensions so the browser reserves space and avoids layout shift.
Keyword-stuffed alt text
Fix: Describe the image naturally; don't cram in keywords.
Eager-loading everything
Fix: Lazy-load below-the-fold images to speed up first paint.
How it works
- 1
Enter a URL
The page whose images you want to check.
- 2
Check
It reads every image and its attributes.
- 3
Fix
See which images need alt text or dimensions.
Frequently asked questions
Every image's alt attribute (missing vs empty vs present), whether width and height are set, and whether images lazy-load.
Alt text describes images for screen readers and search engines, improving accessibility and image-search visibility.
Every image's alt attribute (missing vs empty vs present), whether width and height are set, and whether images use lazy-loading.
Missing means there's no alt attribute at all (a problem); empty (alt="") intentionally marks a decorative image, which is valid.
They let the browser reserve space before the image loads, preventing layout shift (CLS), a Core Web Vital.
It reads the page HTML, so it audits attributes rather than downloading each image to weigh it.
Images injected by JavaScript after load may not appear; it reads the initial HTML.
No. The page is fetched only to analyze its images.
Conclusion
An image SEO checker turns a page full of images into a clear to-do list for alt text, dimensions and lazy-loading — better accessibility, image search and Core Web Vitals. Pair it with the whole-site audit and image compressor to keep images fast and findable.