JP2 to PNG Converter
Convert JP2 to PNG in your browser. JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages; PNG is the better fit for screenshots, logos, graphics and anything that needs transparency. You get a lossless 8-bit PNG with full alpha. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
JP2 expected · other image formats also work
How to use JP2 to PNG
- 1
Add your JP2 files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the PNG is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .png files one at a time or together as a ZIP.
Why use Aback Images for jp2 to png
Where the PNG goes next
PNG opens in every browser, operating system and image editor.
PNG next to JP2
Both sides are lossless, so the size depends on how well the PNG encoder handles this picture compared with the JP2's wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones.
Written without a lossy pass
The PNG is written losslessly, so the pixels decoded from the JP2 arrive unchanged, apart from precision beyond 8 bits per channel.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JP2 vs PNG
What changes from JP2 to PNG
Encoding: the JP2 uses wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones; PNG uses lossless DEFLATE with a prediction filter chosen per row, and the download is a lossless 8-bit PNG with full alpha.
Bit depth: up to 16 bits per channel is common, more is possible in the JP2; PNG allows 1, 2, 4, 8 or 16 bits per channel, and the PNG written here has 8 bits per channel. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
Colour: sRGB, greyscale, YCC or a space described by an ICC profile in the JP2; PNG supports RGB, greyscale, or an indexed palette of up to 256 colours, written here as 8-bit sRGB.
Transparency: the JP2 stores it as an extra component flagged as opacity; the PNG keeps it as a full alpha channel, so edges and shadows can fade smoothly.
Metadata: the JP2 can carry XML, ICC and resolution boxes; PNG can carry text chunks, an ICC profile, physical resolution and EXIF in an eXIf chunk, but nothing is copied across.
About JP2
JPEG 2000 is a wavelet-based format that can be truly lossless or lossy, handles very high bit depths and huge images, and is used where long-term fidelity matters: archives, medicine, satellites and digital cinema.
A .jp2 file is a box structure: a 12-byte signature box, an 'ftyp' box, a 'jp2h' header box with the size and colour specification, then the 'jp2c' box holding the codestream, which begins with FF 4F FF 51.
JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages.
About PNG
PNG stores pixels losslessly with full alpha transparency. It is ideal for screenshots, logos, UI and anything with sharp edges, but photos saved as PNG are several times larger than JPEG.
A PNG opens with an 8-byte signature and is a chain of chunks, each with its own CRC: IHDR (size, depth, colour type), optional PLTE and tRNS for palettes, one or more IDAT chunks with the compressed rows, and IEND.
When converting JP2 to PNG makes sense
PNG is the better choice for screenshots, logos, graphics and anything that needs transparency, while JP2 suits archival masters and specialist imaging.
PNG strengths: Lossless: no quality loss, ever; Full transparency with smooth edges; Perfect for text, screenshots and graphics. Drawbacks to weigh: Large files for photographs; No standard animation (that is APNG).
Limitations
- A JPEG 2000 file may be a lossless master or a lossy derivative; the file does not tell you which at a glance, so keep the original either way.
- Archival scans can be tens of thousands of pixels across, and decoding them needs a lot of memory on a phone.
- A PNG of a photograph is often several times larger than a JPG; PNG pays off for screenshots, graphics and anything with transparency.
- The PNG is written in full colour; Compress PNG can shrink it further with a palette.
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Frequently asked questions
Does converting JP2 to PNG lose quality?
PNG is written losslessly, so the pixels are stored exactly as decoded. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
Is transparency kept in the PNG?
Yes. JP2 stores it as an extra component flagged as opacity, and the PNG is written with an alpha channel, so transparent areas stay transparent.
Which apps open PNG files?
Every browser, operating system and image editor.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.