SEO Audit Hub

Image SEO checker

Find the images on your site that are missing alt text, too heavy, or slowing your pages down.

  • No sign-up to start
  • 138 checks
  • 500 pages free

Image SEO checker: what’s checked

Images are usually the heaviest part of a page and the easiest to get wrong. Missing alt text leaves search engines and screen readers guessing what an image shows; oversized files and missing dimensions slow pages down and make layouts jump while they load.

This checker collects every image across the crawl and reports the problems per image, with the pages that use it — so one fix to a shared banner clears the issue everywhere.

9 Images Images are usually the heaviest thing on a page and the easiest to get wrong. These checks cover alt text, dimensions, modern formats and lazy loading.

  • Below-fold images load eagerly

    Eagerly loading off-screen images wastes bandwidth and slows first paint. Add loading="lazy" to below-the-fold images.

  • Images displayed stretched or squashed

    An image drawn at the wrong aspect ratio looks distorted. Match the width and height attributes or CSS to the file’s proportions, or use object-fit.

    Measured on your homepage with Google PageSpeed Insights.

  • Images missing alt text

    Alt text describes images to screen-reader users and to search engines (helping image search). Add concise, descriptive alt text; leave it empty only for decorative images.

  • Images missing width/height

    Images without width/height cause layout shift as they load. Set explicit dimensions or aspect-ratio.

  • Images too low-resolution for the screen

    An image with fewer pixels than its display size times the screen density looks soft on phones and retina displays. Serve a larger version through srcset.

    Measured on your homepage with Google PageSpeed Insights.

  • Images use legacy formats (jpg/png)

    Modern formats like WebP/AVIF are far smaller than JPG/PNG. Serve next-gen formats to speed up loads.

  • Images without srcset

    Serving one large image to every device wastes mobile bandwidth. Provide srcset/sizes so browsers pick the right size.

  • Inefficient animated GIFs

    Animated GIFs are huge; video is far smaller. Replace them with MP4/WebM video.

    Measured on your homepage with Google PageSpeed Insights.

  • Large image files

    Heavy images slow every page that uses them, and a large hero image is often what decides the page’s Largest Contentful Paint. Resize to the size it is displayed at, compress it, and serve WebP or AVIF.

How it works

  1. 1

    Enter your URL

    Paste your homepage. No account, no install, no verification.

  2. 2

    We crawl your site

    The crawler follows your internal links and runs every check against each page it reaches.

  3. 3

    Get your results

    See your score and issue counts at once. A free account shows every finding, page by page, with how to fix it.

Frequently asked questions

Why does alt text matter for SEO?

Alt text is how search engines understand what an image shows, which matters for image search and for the page’s relevance. It is also what screen readers read aloud.

Does it measure image file size?

Yes — images are probed for their size, and large files are flagged with the pages that load them, heaviest first.

Does it recommend modern formats?

It flags images served in older formats where WebP or AVIF would usually be much smaller, and images that could be lazy-loaded.

Related free tools

Website SEO audit → Crawl your whole site and get a health score, every issue ranked by impact, and a report you can act on — in minutes. Broken link checker → Find every link on your site that leads to an error — and the pages that contain it — with one crawl. Meta tag checker → Check the title and meta description of every page on your site — missing, too long, too short or duplicated — in one crawl.

Ready to check your site?

It takes a couple of minutes and costs nothing.