About this tool
Audit image preload exports before launch so true LCP candidates get early discovery while non-critical assets do not consume bandwidth and parser priority.
The Critical Image Preload Checker analyzes your page's resource hints to determine whether LCP-candidate and hero images have proper preload coverage. It detects missing preload links for above-fold images, flags over-preloading of non-critical assets that wastes bandwidth priority, and reports byte-budget violations when too many images compete for early network slots. The result is a clear action list ranked by LCP impact.
- Parses rows in URL|image|preload|fetchpriority|context|size|media format and normalizes URLs with an optional base URL.
- Flags critical images missing preload hints, missing fetchpriority=high, and conflicting directives such as preload plus low priority.
- Detects duplicate per-page preloads plus count and byte-budget overflow to prevent over-preloading regressions.
How to use Image Preload Checker
Enter a URL and the tool identifies which images are likely LCP candidates based on viewport position and rendered size, then checks the document head for corresponding preload link elements. It reports gaps where critical images lack preload hints and excess entries where below-fold images consume early priority. Apply the recommended changes, then re-run the audit to confirm your preload budget is focused on the assets that matter most.
When this tool is useful
- Audit image preload hints before launching template updates that touch LCP and hero-image rendering.
- Catch missing preload coverage for critical images and over-preloading of non-critical assets in one pass.
- Prioritize pages where preload count or byte budgets are exceeded and likely competing with essential resources.
Practical tips
- Use preload on truly critical LCP candidates only, then pair those rows with fetchpriority=high for clearer browser prioritization.
- Set per-page preload count and byte budgets to prevent template regressions that silently overuse preload hints.
- Avoid duplicate preloads for the same asset and remove below-fold image preloads unless you have measured evidence they are needed.
Examples you can test
These examples show the kind of real input and reviewed output this tool is designed to support. Use them as a starting point before pasting your own production content, then compare the output with the destination system that will use the result. The goal is not only to produce a value, but to make the input assumptions, output format, and review step clear enough that the result can be trusted in a real workflow.
Find a missing LCP image preload
Example input
URL: / | Image: /hero.avif | preload: no | fetchpriority: high | context: hero LCP | size: 180 KB
Expected output
Opportunity: the likely LCP image is high priority but lacks an early preload hint.
For a true hero/LCP image, preload can shorten discovery time when the image would otherwise be found late.
Catch below-fold over-preloading
Example input
URL: /category | Image: /gallery-12.webp | preload: yes | fetchpriority: auto | context: below fold gallery | size: 260 KB
Expected output
Waste risk: a below-fold image is consuming preload bandwidth before critical assets finish.
Preloading too many non-critical images can make the page slower even though every individual hint looks intentional.
Validation checklist
Run through these checks before copying the result into a CMS, codebase, spreadsheet, campaign, support ticket, or production document. Small formatting differences, unit assumptions, hidden whitespace, and platform-specific rules are common sources of mistakes in quick browser tools, so the final review should happen in the same context where the output will be used.
- Confirm each preloaded image is actually used on the page and is visible early enough to justify the hint.
- Keep preload count low per page so the browser's early network slots stay focused on the likely LCP asset.
- Align critical image preload hints with `fetchpriority="high"` and eager loading when the image is a true LCP candidate.
- Remove duplicate or below-fold image preloads unless measured data shows they improve user-perceived performance.
Why people use this tool
Without a preload hint, the browser cannot begin fetching an LCP image until it has parsed the HTML, built the render tree, and discovered the resource in markup or CSS. That discovery delay directly inflates Largest Contentful Paint times, especially on slower connections. Conversely, over-preloading non-critical images can saturate early bandwidth and push truly important resources later in the queue, making disciplined preload management essential for fast page loads.
Related search intents
critical image preload checker, preload image seo checker, rel preload image audit, lcp preload validator.