Lossless Mode Next-Gen Format Never Saved to Disk

Convert PNG to JPEG XL

Re-encode PNG files to JPEG XL — a true lossless mode that's smaller than PNG, with full transparency and 16-bit colour preserved.

Browser support note: JPEG XL requires a browser flag in Chrome 145 and is not yet enabled by default. Best suited for archiving, internal tooling, and future-proofing workflows. Use AVIF or WebP for live web delivery today.

Why convert PNG to JPEG XL?

PNG is lossless and universal, but its files are large — especially for screenshots, UI exports, and high-resolution design assets. JPEG XL keeps everything PNG gives you — full alpha transparency, a true lossless mode, and up to 16-bit colour — while encoding the same pixels into a noticeably smaller file.

JXL's lossless mode is a natural fit for PNG content: flat colour regions, sharp edges, and text compress extremely well, so a lossless JXL is typically smaller than the original PNG with zero quality loss. For photographic PNGs, switching to JXL's lossy mode shrinks files even further.

Best Use Cases in 2026

  • Shrinking large PNG screenshots and UI exports
  • Lossless archiving of logos and design assets
  • Transparent graphics at maximum quality
  • 16-bit and HDR PNG preservation
  • Future-proofing for browser adoption
  • Apps and tools with JXL codec support
Does JPEG XL preserve my PNG's transparency?
Yes. JPEG XL supports a full alpha channel, so transparent areas in your PNG stay transparent in the output — no white background, no fringing.
Is the conversion lossless?
JPEG XL has a true lossless mode that reproduces your PNG pixel-for-pixel, usually at a smaller file size. For photographic PNGs where a little compression is acceptable, JXL's lossy mode goes much smaller again. Use Magic Flow to specify — for example, 'convert to JPEG XL, lossless'.
Can I use JXL files on my website today?
With caveats. Chrome 145 added JXL decoding but it requires enabling a browser flag — it's not on by default. Firefox and Safari support is still limited. For live web delivery, use AVIF or WebP with JXL as an optional progressive enhancement via a <picture> element. For archiving or internal tooling, JXL works well right now.
Can I convert formats other than PNG?
Yes. This page is tuned for PNG, but the uploader also accepts JPG, WebP, AVIF, HEIC/HIF and SVG — everything is converted to JPEG XL. If you mainly work with JPGs, the dedicated JPG to JPEG XL tool is a better starting point.
Are my files stored anywhere?
Never. Mochify processes everything in memory and wipes the data immediately after your download completes. No copies are kept on our servers.

PNG alternatives: choosing the right format

FormatTransparencyLosslessBrowser supportBest for
JPEG XL This page✓✓ (smaller than PNG)Partial (flag required)Archiving, internal tooling, future-proofing
AVIF ✓✓ (limited)~95% globalModern web — best compression for live delivery
WebP ✓✓~97% globalBroad compatibility — CMSes, email, social
PNG ✓✓100%Legacy tools, print, universal compatibility

Also available

JPG to JPEG XL →

Future-proof your photo library with next-gen compression

SVG to JPEG XL →

Rasterise vector assets to JXL with transparency