speed-lens

Enter a URL — it pulls a PageSpeed Insights audit and loads the page in a real browser to measure every image's actual rendered size, then shows the bytes you can save by resizing + WebP. Optimized images ready to download.

Tip: paste a product or landing page — that's where oversized hero images usually hide.

41Perf

https://www.allbirds.com/products/mens-wool-runners

mobile · viewport 1366×900 @1x · 30 images (+41 offscreen) · 29d ago

＋ New audit

SlowExpert read of this page's load speed

Lighthouse scores this page 41/100 on mobile — slow. The main drag is Largest Contentful Paint, First Contentful Paint, Speed Index, and Time to Interactive (29.4 s, 8.9 s, 12.4 s, 36.0 s). Compress/preload the LCP image and cut render-blocking CSS & JS. On image weight specifically, you're shipping 7.5 MB (93%) more than needed across 30 images — and since LCP is weak, right-sizing the hero image is the single highest-leverage fix here.

Cut 7.5 MB of image weight (resize to render size + WebP) — see the table below.
Largest Contentful Paint (29.4 s): compress/preload the LCP image and cut render-blocking CSS & JS.
First Contentful Paint (8.9 s): lower server response time (TTFB) and remove render-blocking resources.
Speed Index (12.4 s): prioritize above-the-fold content and defer offscreen work.
Time to Interactive (36.0 s): reduce JavaScript execution and defer non-critical scripts.

Real-world data — Chrome UX Report, 28-day p75 from real visitors

LCP

3.9 s

FCP

1.6 s

INP

208 ms

CLS

0.02

TTFB

1.1 s

Lab metrics — Lighthouse simulated

Largest Contentful Paint

29.4 s

how long until the biggest thing above the fold (usually the hero image or headline) finishes painting — a problem here (target ≤ 2.5s).

First Contentful Paint

8.9 s

how long until the very first text or image shows up — a problem here (target ≤ 1.8s).

Speed Index

12.4 s

how quickly the page visually fills in — a problem here (target ≤ 3.4s).

Total Blocking Time

570 ms

how long the main thread was frozen — i.e. how long taps/clicks feel dead — needs work here (target ≤ 200ms).

Cumulative Layout Shift

how much the layout jumps around while loading — healthy here (target ≤ 0.1).

Time to Interactive

36.0 s

how long until the page reliably responds to input — a problem here (target ≤ 3.8s).

GTmetrix — independent test · full report ↗

Grade

Performance

Structure

Page weight

7.8 MB

Requests

456

Largest Contentful Paint

1.2 s

First Contentful Paint

715 ms

Total Blocking Time

1.5 s

Cumulative Layout Shift

0.000040958

Speed Index

1.2 s

Time to Interactive

11.7 s

Fully Loaded Time

11.7 s

Time to First Byte

124 ms

Conclusion — image weight you can cut (resize to render size + WebP)

−7.5 MB (93% lighter)

after 549.1 KBsaved 7.5 MB

29 of 30 images optimizable 29 oversized for their slot 29 not in a modern format Biggest win: −575.3 KB (Allbirds_WL_RN_SF_PDP_Natural_Grey_TOP_953b097d-4be6-46d7-9e17-dacf4fc8a60b)

Images by savings

Allbirds_WL_RN_SF_PDP_Natural_Grey_TOP_953b097d-4be6-46d7-9e17-dacf4fc8a60b

imgpng

↳ oversized: 1024px served for a 585px slot↳ format: png → webp

1024×1024 → shown 585×585 · 607.2 KB → 31.8 KB

−575.3 KB

95% smaller

speed-lens

Real-world data — Chrome UX Report, 28-day p75 from real visitors

Lab metrics — Lighthouse simulated

GTmetrix — independent test · full report ↗

Images by savings

PageSpeed opportunities — 3 fixable issues

Diagnostics