Screenshots, UI mockups, exported charts, logo files — PNG collections grow fast, and nearly every file in them is larger than it needs to be. PNG compression dates to the mid-1990s, and modern codecs can represent the same pixels in far less space. JPEG XL is the most capable of the successors: it handles photographic content and sharp-edged graphics equally well, keeps full alpha transparency, and routinely produces files a fraction of the size of the PNG original. Whether you are archiving a large image library, tightening an asset pipeline, or simply reclaiming disk space, swapping PNG for JXL is one of the highest-leverage moves available.
Everything here happens locally. The converter loads a WebAssembly encoder into your browser and does the work on your machine — no upload, no queue, no account, no charge. That matters more than usual for this particular pair, because PNGs are so often screenshots, and screenshots tend to contain things nobody should paste into a stranger's server: dashboards, private conversations, internal tools. On this page they never leave your computer — the only thing that ever comes down the wire is the encoder itself, about 5 MB fetched once and cached by your browser.
The quality slider defaults to 85, which keeps graphics crisp while still cutting size substantially; push it higher when the source is precious, lower when storage is the priority. Transparency comes through intact, since JPEG XL has first-class alpha support — logos and UI elements keep their clean edges. One honest caveat before you convert an entire library: software for viewing JPEG XL is still thin on the ground. Among major browsers only Safari displays it natively, so JXL currently makes the most sense for storage, for pipelines you control, or for tools you have confirmed can read it — not yet for files you plan to send to arbitrary recipients.
Why convert PNG to JPEG XL?
- JPEG XL typically compresses the same image far smaller than PNG, especially screenshots and flat graphics
- Alpha transparency is fully preserved — no white boxes behind logos or UI elements
- A quality slider (default 85) trades between maximum savings and near-pristine output
- Nothing is uploaded — sensitive screenshots stay on your own machine
- Free, no account required, with the encoder cached by your browser after the first use
How it works
- Step 1
Drop your files
Drag your PNG files into the converter above, or click “Choose files”. Batches are welcome.
- Step 2
Pick your settings
JPEG XL is preselected. Adjust quality or size if you want, or keep the defaults.
- Step 3
Convert and download
Conversion runs locally in your browser. Download files individually or grab everything as a zip.
Frequently asked questions
- My PNGs are screenshots of internal tools — is it safe to convert them here?
- Yes. The encoder is WebAssembly running inside your browser, and your images are never transmitted anywhere. If you want to verify that, watch the network tab in your browser's developer tools during a conversion — your screenshots never appear in any outgoing request.
- Does JPEG XL support transparency the way PNG does?
- It does. JPEG XL carries a full alpha channel, so transparent backgrounds, soft shadows, and anti-aliased edges survive the conversion without being flattened onto a solid color.
- Will I actually be able to open the JXL files afterward?
- Check before committing. Safari displays JPEG XL natively, but other major browsers do not yet, and application support varies. Image tools are adopting it steadily, but if you are unsure, keep the PNG originals until everything in your workflow reads JXL.
- Is the conversion lossless?
- The output is controlled by the quality slider, and at the default of 85 the compression is lossy — visually very close to the source, but not bit-identical. Raising the slider narrows the gap further. If you need a guaranteed pixel-exact copy, hold on to the PNG as your master.