JPEG 2000 to PNG converter

JP2 → PNG is the lossless way out of JPEG 2000, the one to use when the image carries 16-bit data, transparency or a palette you need to keep.

Converted with Image engine · input deleted within 24 h
Free: 5 conversions a day · 5 MB each
Higher limits →

From real runs

What you get — and what changes

Element	Result	What happens
16-bit samples	Kept	The 64×64 16-bit grayscale test file was written as a 16-bit PNG with the same values, 291 to 694 (3,932 → 4,807 bytes).
Alpha	Kept	An RGBA codestream and a gray-plus-alpha logo kept their transparency as RGBA and LA PNGs.
Palette images	Kept	A 768×512 colour-mapped conformance file stayed a palette PNG of 222,402 bytes.
Resolution box	Kept	The display resolution stored in the JP2 header (72 dpi in the relax.jp2 sample) was written to the PNG's pHYs chunk.
File size and time	Changed	Lossless PNG is big and slow for large images: the 4096×4096 solar image gave 5,198,403 bytes in 16 to 24 s, the 2717×3701 balloon print 13,126,488 bytes in 50 s.
Very large scans	Lost	A 67-megapixel scan did not finish within our conversion time limit as PNG, while JPG finished in 35 s. Use JPG, or resize with width, for scans that big.
Lossy JP2 artefacts	Kept	If the JP2 was saved lossy, its wavelet blur and ringing are copied into the PNG exactly; PNG adds no loss of its own.
XML boxes	Lost	Embedded XML, including the FITS header in solar observatory files and rights statements in archive files, is not carried over.

16-bit samples Kept
The 64×64 16-bit grayscale test file was written as a 16-bit PNG with the same values, 291 to 694 (3,932 → 4,807 bytes).
Alpha Kept
An RGBA codestream and a gray-plus-alpha logo kept their transparency as RGBA and LA PNGs.
Palette images Kept
A 768×512 colour-mapped conformance file stayed a palette PNG of 222,402 bytes.
Resolution box Kept
The display resolution stored in the JP2 header (72 dpi in the relax.jp2 sample) was written to the PNG's pHYs chunk.
File size and time Changed
Lossless PNG is big and slow for large images: the 4096×4096 solar image gave 5,198,403 bytes in 16 to 24 s, the 2717×3701 balloon print 13,126,488 bytes in 50 s.
Very large scans Lost
A 67-megapixel scan did not finish within our conversion time limit as PNG, while JPG finished in 35 s. Use JPG, or resize with width, for scans that big.
Lossy JP2 artefacts Kept
If the JP2 was saved lossy, its wavelet blur and ringing are copied into the PNG exactly; PNG adds no loss of its own.
XML boxes Lost
Embedded XML, including the FITS header in solar observatory files and rights statements in archive files, is not carried over.

Sample conversions

Solar observatory image

Input: aia171.jp2, 1,078,612 bytes, 4096×4096 8-bit grayscale.
Output: 5,198,403-byte grayscale PNG in 16 to 24 s across two runs.

16-bit grayscale

Input: 16bit.cropped.jp2, 3,932 bytes, 64×64, 16 bits per sample.
Output: 4,807-byte 16-bit PNG in 5 ms with values unchanged; most viewers show it very dark because the values sit low in the 16-bit range.

JPEG 2000 conformance photo

Input: file1.jp2, 650,678 bytes, 768×512 RGB.
Output: 684,525-byte PNG in 0.6 s.

A real JPEG 2000 → PNG run

We converted our JPEG 2000 sample (42 KB) with Image engine on 2026-10-20. It took 1.6 s and produced a 302 KB PNG file, 7.2× larger than the input. The engine raised 1 warning, listed below.

Input · sample.jp2 · 42 KB

43,179 bytes

Output · sample.png · 302 KB

480 × 600 px, 8-bit, colour type 2

Width: 480
Height: 600
Encoding: 8-bit, colour type 2

Image metadata stripped from output.

Is your file a scan?

A PNG of a page scan is still a picture of text. For searchable or editable text, run the PNG through the screenshot-to-text workflow, which uses AI Deep Read.

Options and when to change them

width: Use it for large scans that would otherwise make a huge PNG; fewer pixels also means less time spent compressing.
height: Use with width and fit when every page of a scanned set has to come out the same size.

Do it yourself

OpenJPEG

bash

opj_decompress -i image.jp2 -o image.png

Keeps 16-bit samples, and -r 1 decodes at half size when you only need a preview.

Python (Pillow)

bash

from PIL import Image

im = Image.open("scan.jp2")
im.reduce = 1  # optional: decode at half size, much faster
im.save("scan.png")

JPEG 2000 to PNG by API or MCP

The HTTP API and the MCP server run the exact engine this page uses (Image engine); the response carries the same warnings the web converter shows. Check support first with GET /api/v1/pairs?from=jp2&to=png.

curl

curl -X POST https://filetypeconverters.com/api/v1/convert \
  -H "Authorization: Bearer $FTC_API_KEY" \
  -F "file=@input.jp2" -F "from=jp2" -F "to=png" \
  -F 'options={"width":0}' \
  --output output.png

Options this engine accepts for JPEG 2000 → PNG

Key	Applies to	Type	Default
width	Writing PNG	number	0
height	Writing PNG	number	0
fit	Writing PNG	contain · cover · fill	contain
quality	Writing PNG	number	90
background	Writing PNG	string	#ffffff
stripMetadata	Writing PNG	boolean	true

API reference

When this is the wrong conversion

If the JP2 is a photo or a page scan for reading on screen, JP2 → JPG is several times smaller and much faster.
If you need the metadata from an observatory or archive file, read it from the JP2 itself; the PNG will not contain it.

JPEG 2000 to PNG questions

Does PNG keep 16-bit JPEG 2000 data?

Yes for grayscale: our 16-bit test file came out as a 16-bit PNG with identical values. It is the route to use for medical, scientific and satellite images, which JPG would reduce to 8 bits.

Why is the PNG so much bigger than the JP2?

JPEG 2000 files are usually saved lossy and compress far better than PNG's lossless deflate. The balloon print went from 628,654 bytes to 13,126,488 bytes as PNG.

Why does my 16-bit PNG look almost black?

Many sensors fill only the bottom of the 16-bit range; our sample used values up to 694 out of 65,535. The data is intact, and stretching levels in an image editor makes it visible.