JPEG 2000 to PGM converter
Convert JPEG 2000 to PGM in seconds, free and unlimited. No upload, no sign-up, no watermark: your image never leaves your device.
Last updated
Quick answer: To convert JPEG 2000 to PGM, add the JPEG 2000 file to the iHateFiles JPEG 2000 to PGM converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. A straight swap between two raster formats, at full resolution.
Should you convert JPEG 2000 to PGM?
Do this when you are about to edit the file and want no further loss. Do not do it hoping to improve a JPEG 2000: PGM preserves what it is given, including the damage.
JPEG 2000 is lossy and PGM is not
Moving from JPEG 2000 to PGM stops any further loss, but it cannot undo what JPEG 2000 already discarded: that detail was thrown away when the file was first written and is not in it any more. Expect the PGM to be considerably larger while looking exactly the same, because it is now storing the JPEG 2000 artefacts faithfully too.
PGM reduces the colour first
Before PGM compresses anything it reduces the image to greyscale. Flat colour, logos and line art survive that easily. A photograph coming from JPEG 2000 will band visibly, and no quality setting changes it, because the limit is the format rather than the encoder.
Expect a much larger file
PGM stores every pixel exactly, including the compression artefacts the JPEG 2000 already has. The file will grow, sometimes by a factor of ten, without looking any better. Do this when you need to edit without further loss, not to improve the image.
JPEG 2000 and PGM side by side
| JPEG 2000 | PGM | |
|---|---|---|
| Compression | Lossy | Lossless |
| Transparency | No | No |
| Animation | No | No |
| Written here | No | Yes |
What usually goes wrong
About the JPEG 2000. It is technically better than JPEG and lost anyway. Support, not quality, decided it.
About the PGM. Converting a colour image to PGM throws the colour away for good. Keep the original if you might want it back.
How to convert JPEG 2000 to PGM
- Add your JPEG 2000 file. It is read from your disk and stays there.
- Check the settings. The output format is already set to PGM.
- Press convert and the PGM file is saved back to your device.
Questions
How do I convert JPEG 2000 to PGM?
Open this page, add your JPEG 2000 file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this JPEG 2000 to PGM converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to PGM lose quality?
PGM compresses without loss, but it first reduces the image to greyscale, discarding all colour. Flat colour and line art come through unchanged; a photograph will band and lose subtlety.
Can I convert several JPEG 2000 files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.