PNG Compressor. Free, private, no upload.
Cut PNG screenshots, graphics and logos down by half or more. Transparency survives, text stays crisp, and no pixel ever leaves your device.
PNG files are big for a simple reason: the format stores up to sixteen million colors even when an image uses a few hundred. The classic fix is palette reduction, rebuilding the image on a carefully chosen set of up to 256 colors with dithering to keep gradients smooth. Done well it is invisible and routinely halves a screenshot. Filexum runs that trick, plus a lossless optimizer pass, inside your browser: each PNG is quantized, checked against the original for banding and color shift, and only shipped if it passes. If your PNG would not survive it, you get the lossless result instead.
How it works
- 1 Drop PNG files into the box above: screenshots, exported graphics, logos with transparency, whole folders of them.
- 2 Auto mode reduces each image to its ideal palette and verifies the result still matches the original, then an optimizer squeezes the encoding itself. Set Manual to 100 if you need strictly lossless.
- 3 Slide the before and after divider over any result to check edges and gradients, then download files or the batch as a .zip.
Yes. Nothing is uploaded, so nothing is metered.
Server-based compressors have to limit you: every image they take costs them compute and bandwidth, and your photos sit in their infrastructure while it happens. Filexum does the work inside your browser instead. That is both the privacy story and the reason there are no quotas here. Switch off the Wi-Fi and it keeps compressing, which is all the proof you need that your images stay with you. See how on the how we can't see your files page.
- Your images are uploaded to a stranger's server
- Monthly quotas, batch caps and size ceilings
- The good limits sit behind a paid plan
- Needs a working internet connection
- Images are compressed on your device, nothing is uploaded
- No quotas or caps: your hardware does the work
- Everything is free, there is no server bill to cover
- Works with the Wi-Fi off, because nothing is ever sent
What to expect
| Content | Typical saving | Notes |
|---|---|---|
| Screenshots of apps and pages | 50 to 80% | Text and UI stay pixel-sharp |
| Logos and icons with transparency | 60 to 90% | Alpha fully preserved |
| Photos saved as PNG | 60 to 80% | Palette trick plus dithering |
| Already indexed or tiny PNGs | 0 to 20% | Lossless pass only, never larger |
Measured on real photos and screenshots. Your numbers depend on how the files were made; the one guarantee is that a file never comes back larger.
Frequently asked
Is transparency preserved?
Fully. Alpha channels survive compression, including soft shadows and anti-aliased edges. A transparent logo comes back transparent, just several times smaller.
Will text in my screenshots stay sharp?
Yes. Palette reduction does not blur anything: every pixel keeps a hard value, which suits text and UI edges perfectly. That is why screenshots are the ideal input and often shrink the most.
Is PNG compression here lossless?
Two modes. Auto uses palette reduction, which changes pixel values slightly but is verified against the original before being accepted, so it looks the same. Manual at 100 skips palette work entirely and only runs the lossless optimizer, so pixels stay bit-identical.
Why do PNG photos shrink so dramatically?
A photographic PNG stores millions of slightly different colors that the eye reads as a few hundred. Mapping them onto an optimized 256 color palette with dithering keeps the look while storing one byte per pixel instead of three or four. This is the single biggest lever any PNG tool has.
When should I not compress a PNG this way?
If the file is an archival master, a print asset or an image you will keep editing, keep the original or use Manual 100 for the lossless pass. For anything headed to a web page, a chat, a doc or an email, Auto is the right default.
Are there limits on files or sizes?
None. No monthly allowance, no cap per batch, no maximum file size. Your device does the work, so scale costs nothing. Big batches stream through a couple of files at a time to keep memory in check.
Do my screenshots get uploaded anywhere?
No, and screenshots are exactly why that matters: they tend to contain names, messages and internal tools. Everything is processed by code running in this page. Open your browser's Network tab and watch it stay empty as proof.