PNG · oxipng · Lossless toggle

Compress PNG
keep transparency
when you need it

Shrink PNG screenshots and UI graphics locally. oxipng with optional lossless — strip metadata, keep alpha, batch a folder offline.

Download for Windows Lossless vs lossy →
PNG · oxipng · Transparency · Offline
84.5% png→webp avg99.8% peak545 files png → webp at 85
Lossless

Two modes for PNG

Screenshots and UI need different handling than photos. Choose per batch.

Lossless — Bit-exact, alpha preserved. Strips metadata and recompresses structure. No quality slider needed.
Lossy + keep alpha — When size matters most, allow lossy PNG/WebP conversion while keeping transparency where possible.
Convert to WebP — Smallest for web. Transcode the batch to WebP in one pass — see Compress WebP.
Proof

Measured on 545 PNGs — real vips

545 PNGs from Wikimedia Commons, convert PNG → WebP at quality 85 balanced — real vips. 247.9 MB → 40.4 MB avg 84.5% peak 99.8%.

FileBeforeAfterSaved
04_Hegasy_Hand.png721 KB189 KB WebP−73.8%
100_Hall_interaction.png42.6 KB11.0 KB WebP−74.2%
123inkt_logo.png14.4 KB4.0 KB WebP−72.2%

84.5% avg, 99.8% peak on 545 files — real vips, not dry estimate.

Best format

Smallest for web

84.5%
png→webp avg

247.9 MB → 40.4 MB

99.8%
peak

On 545 files

545 files
png → webp at 85
Bit-exact
transparency

Alpha preserved

How it works

PNG in three steps

01 01
Select PNGs

Choose a folder, filter to PNG. Check what you want.

02 02
Choose mode

Lossless toggle, or allow conversion. Preview per file.

03 03
Batch

Run locally, backups to /backup.

Related

Next for PNG

Compress to 100KB

Hit a size target. 100KB →

FAQ

PNG — FAQ

Will transparency be preserved?

Yes. Lossless keeps alpha bit-exact. Lossy/WebP keeps alpha where the target format supports it.

Is PNG compression lossless by default?

Toggle on → lossless (metadata only). Toggle off → allows more aggressive shrinking and optional WebP conversion.

Do I need to upload?

No. All PNG processing is local. No upload, no account.

PNG · oxipng

Make PNGs smaller. Keep what matters.

Lossless when you need it, smaller when you don’t — all offline.

Download for Windows Compress WebP →
Offline · Transparency · Windows