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JPG / PNG / WebP · processed in your browser
Largest Contentful Paint
Upload an image to measure LCP.
Delivery parameters — see the markup change
Image optimizationresize to 1000px + WebP compression
Preload hint<link rel="preload" as="image">
Reserve width / heightprotects CLS, not LCP
loadinglazy defers an above-fold hero
fetchpriorityhint the browser's queue
decodingsync can block the paint
Connectionsimulated bandwidth
what you're shippingmarkup
<!-- upload an image to generate markup -->
LCP model: start = latency + discovery (preload removes it, lazy adds it, fetchpriority shifts it) · download = bytes ÷ bandwidth (optimization shrinks bytes) · render = measured decode (sync adds a paint-blocking penalty). Directional and transparent, not a lab-accurate trace.