A reproducible 100-scene browser report with category-level PNG, JPEG and WebP file sizes, encoding times, matched sampled PSNR and downloadable source data.
Direct answer · browser image compression report 2026
What did the published reference run find?
In the published Brave and Windows run, WebP reduced the median file size versus the same-scene PNG baseline, but encoded more slowly than JPEG on that device. The report separates opaque and transparent comparisons.
Evidence on this page
The landing page links to the exact source JSON, methodology and source hashes used to produce the tables.
Important limit
The results describe one synthetic corpus, browser and machine and must not be generalized to every image or encoder.
Published reference run · 30 July 2026
Headline measurements
100deterministic scenes across four categories78.2%median WebP saving versus same-scene PNG at quality 8257.1%smaller WebP files at near-matched sampled PSNR across opaque scenes17.0 msmedian WebP browser encode time on the published device
Trade-off: WebP was smaller in the published opaque-scene comparison, while browser encoding was slower than JPEG on that device. This is a measured reference run, not a universal winner claim.
WebP saving versus same-scene PNG by category
Photo-like detail92.8%
Interface and text54.1%
Transparent graphic83.6%
Flat illustration72.4%
Category table
Scene category
PNG median
JPEG 82 saving
WebP 82 saving
Photo-like detail
527.9 KB
90.2%
92.8%
Interface and text
10.1 KB
-95.9%
54.1%
Transparent graphic
266.4 KB
91.2%
83.6%
Flat illustration
55.4 KB
51.5%
72.4%
Corpus
Twenty-five deterministic scenes were generated in each category: photo-like detail, interface/text, transparent graphics and flat illustrations.
Timing
Each output used one discarded warm-up and three measured encodes. The published time is the median of those measurements.
Quality comparison
The matched run sampled five quality levels over 24 scenes. Transparent JPEG comparisons were excluded from the opaque headline because JPEG flattened alpha.