PNG to JXL Converter
FileFlip converts PNG to JXL entirely inside your browser, using ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a PNG file to JXL?#
- Drop your PNG file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to JXL and the conversion starts on its own. FileFlip downloads 14.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick on your own machine.
- Save the JXL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting PNG to JXL lose quality?#
It depends on what is inside the file. PNG is a container rather than a codec, so whether the JXL conversion copies the streams across untouched or re-encodes them is decided by the codecs that particular file happens to use.
Is it safe to convert PNG files online?#
Yes, because nothing is uploaded. FileFlip converts PNG files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What PNG to JXL actually does to the file#
Converting PNG to JXL runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, re-encodes or copies through depending on the codecs in the file, keeps EXIF metadata, ICC colour profile and transparency.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: PNG → JXL |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Decided by the codecs inside the file |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| EXIF metadata | Kept | Carried through into the converted file. |
| ICC colour profile | Kept | Carried through into the converted file. |
| Transparency | Kept | Carried through into the converted file. |
What is a PNG file?#
A PNG file stores a raster image using lossless DEFLATE compression, which is why screenshots, logos, and graphics with flat colour or sharp edges use it instead of JPEG.
Use PNG for screenshots, logos, icons, and any graphic with flat colour or transparency, where exact pixel reproduction matters more than file size.
Convert PNG to JPEG or WebP when the image is a photograph and file size matters more than pixel-perfect reproduction, since a photographic PNG is typically several times larger than an equally sharp lossy file.
What is a JXL file?#
A JXL file stores an image under the JPEG XL coding system, a format built to losslessly repackage an existing JPEG into a smaller file or to encode a new photo at higher quality per byte than JPEG, WebP or AVIF.
Use JPEG XL for archiving and photo libraries where you want smaller files than JPEG without giving up the option to reconstruct the original JPEG exactly, especially once Chrome and Firefox finish rolling out default decoding.
Convert JXL to JPEG or PNG for anything going on the web today, since most browsers still require a manual flag to display JPEG XL directly.
PNG to JXL questions people ask#
Is PNG lossless?
Yes, PNG is always lossless. It compresses image data with the DEFLATE algorithm, the same family of compression used in ZIP files, so every pixel decodes back exactly as it was encoded. There is no lossy PNG mode, unlike JPEG.
Does PNG support animation?
A standard PNG file does not animate; it holds exactly one image. Animated PNG (APNG) is a separate extension, created by Mozilla developers in 2008 and folded into the official PNG specification in 2025, that stores multiple frames inside a file that still uses the .png extension. All major browsers now play APNG frames, but many image editors and older viewers only show its first frame, so GIF or WebP remain more reliable choices when animation has to work everywhere.
Why is my PNG file so much bigger than the same photo saved as JPEG?
PNG's DEFLATE compression is lossless, so it has to encode every bit of the noise and subtle colour variation a photograph contains. JPEG gets its smaller size by discarding detail the eye barely notices, which a lossless format like PNG can't do. PNG stays efficient for flat-colour graphics like screenshots or logos; it's photographs where the size difference shows up.
Does PNG support transparency?
Yes, PNG supports transparency through an alpha channel, letting each pixel be fully opaque, fully transparent, or partially see-through. It works on both truecolour and palette-based PNGs, which is why PNG is the standard choice for logos and icons that need to sit on any background.