Lazy Load Checker — Verify Deferred Image Loading
Check if images on any URL use lazy loading correctly. Identify images missing loading='lazy' that are hurting your LCP and page load speed. Free tool.
What is a Lazy Load Checker?
The Lazy Load Checker fetches any URL and examines every img element, checking whether it has loading="lazy" set. Results are split into two groups: images with lazy loading implemented, and images without. For images below the fold that lack the attribute, the tool flags them as opportunities to reduce initial page weight and improve Largest Contentful Paint.
When Should You Use Lazy Load Checker?
Use this as part of a performance audit for any page with multiple images — e-commerce product listings, gallery pages, blog posts with embedded images, and any long-form content page. Lazy loading defers the download of images outside the initial viewport, reducing the amount of data transferred on page load and improving time-to-interactive on slower connections. It is one of the simplest performance wins available with no JavaScript required.
How to Read Lazy Load Checker Results
Note that the LCP image — typically the largest image above the fold — should not have lazy loading applied. Lazy-loading the LCP element tells the browser to delay fetching it, which directly worsens your LCP score. The correct pattern is to leave above-the-fold images without the attribute and apply loading="lazy" to everything below the fold. The tool indicates which images are likely above the fold to help you apply this correctly.
What Should You Know Before Using Lazy Load Checker?
Adding loading="lazy" is a single attribute change supported by all modern browsers. For WordPress sites this can be enabled site-wide through your image optimisation plugin or theme performance settings. After making changes, re-run the PageSpeed Score Checker or Core Web Vitals Checker to confirm LCP has improved and no above-the-fold images were accidentally lazy-loaded in the process.
Frequently Asked Questions
What is lazy loading for images?
Lazy loading defers the download of images that are outside the browser's current viewport until the user scrolls near them. Applied via the loading="lazy" HTML attribute, it reduces the initial page weight — the amount of data downloaded on first load — improving time-to-interactive and Largest Contentful Paint for image-heavy pages.
How do I add lazy loading to images?
Add loading="lazy" to any img element: <img src="photo.jpg" alt="Description" loading="lazy">. This is a native browser feature supported by all modern browsers and requires no JavaScript. For WordPress sites, lazy loading can be enabled site-wide through performance plugins or theme settings without touching individual image elements.
Should the hero image be lazy loaded?
No. The hero image — typically the largest image above the fold and the Largest Contentful Paint element — should never have loading="lazy". Lazy loading the LCP image delays its download until the browser processes the attribute, directly worsening your LCP score. Leave above-the-fold images without the lazy attribute; apply it only to images below the fold.
How does lazy loading affect Core Web Vitals?
Correctly applied lazy loading improves LCP by reducing the initial data downloaded before the LCP element can render. It also improves Total Blocking Time and Time to Interactive. Applied incorrectly to the LCP image, it worsens LCP significantly. The Lazy Load Checker identifies which images have the attribute and flags the LCP image if it is incorrectly lazy-loaded.
Does lazy loading affect SEO?
Lazy loading correctly implemented does not hurt SEO — Googlebot supports native lazy loading and renders JavaScript lazy-loading implementations as well. However, Google recommends using native loading="lazy" over JavaScript-based approaches for reliability. Ensure your lazy-loaded images have appropriate alt text and are not blocked by robots.txt.
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