About this tool
Review image-loading exports before launch so critical images are not deferred, non-critical assets are not over-prioritized, and Core Web Vitals risk stays controlled.
The Image Lazy Loading Checker audits loading attribute usage to ensure above-fold and LCP-critical images load eagerly while below-fold content images properly defer with loading=lazy. It also evaluates fetchpriority hints to confirm that hero images receive high priority without competing with non-critical assets.
- Parses rows in URL|image|loading|fetchpriority|context|size format and normalizes page URLs with an optional base URL.
- Flags lazy-loaded critical images, eager below-fold images, high-priority misuse, and directive conflicts.
- Supports configurable below-fold eager payload budgets and per-page high-priority limits for practical remediation triage.
How to use Lazy Loading Checker
Supply image data including each image's loading attribute, fetchpriority value, viewport position, and criticality flag. The tool checks that LCP candidates are not lazy-loaded, below-fold images are deferred, and fetchpriority=high is reserved for the assets that actually need it.
When this tool is useful
- Audit loading and fetchpriority directives before launching templates, migrations, or performance-focused releases.
- Catch lazy-loaded hero/LCP images that can delay rendering and hurt Core Web Vitals.
- Prioritize non-critical images still marked eager or high-priority when they should defer.
Practical tips
- Keep above-fold and LCP images eager with clear high fetch priority, then lazy-load non-critical media by default.
- Set a byte budget for eager below-fold assets so accidental template regressions are easier to catch.
- Limit per-page high-priority images to only the truly critical visual assets to avoid resource contention.
Why people use this tool
Lazy-loading an LCP image is one of the most damaging performance anti-patterns because it delays the browser from even requesting the most important visual element until JavaScript executes. Conversely, eagerly loading dozens of below-fold images wastes bandwidth and competes with critical resources, making correct loading attribute assignment essential for Core Web Vitals.
Related search intents
image lazy loading checker, loading lazy audit, above the fold image loading checker, native lazy load seo tool.