PNG to JP2 Converter
Convert PNG to JP2 in your browser. PNG files usually come from screenshots, design exports, logos and web graphics; JP2 is the better fit for archival masters and specialist imaging. You get a lossless JPEG 2000 (.jp2) using the reversible 5/3 wavelet. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
PNG expected · other image formats also work
How to use PNG to JP2
- 1
Add your PNG files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the JP2 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 .jp2 files one at a time or together as a ZIP.
Why use Aback Images for png to jp2
Where the JP2 goes next
JP2 opens in macOS Preview, GIMP, IrfanView, XnView, ImageMagick and the OpenJPEG tools.
JP2 next to PNG
Both sides are lossless, so the size depends on how well the JP2 encoder handles this picture compared with the PNG's lossless DEFLATE with a prediction filter chosen per row.
Written without a lossy pass
The JP2 is written losslessly, so the pixels decoded from the PNG 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.
PNG vs JP2
What changes from PNG to JP2
Encoding: the PNG uses lossless DEFLATE with a prediction filter chosen per row; JP2 uses wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones, and the download is a lossless JPEG 2000 (.jp2) using the reversible 5/3 wavelet.
Bit depth: 1, 2, 4, 8 or 16 bits per channel in the PNG; JP2 allows up to 16 bits per channel is common, more is possible, and the JP2 written here has 8 bits per channel. 16-bit PNGs from photo and scientific software are reduced to 8 bits per channel.
Colour: RGB, greyscale, or an indexed palette of up to 256 colours in the PNG; JP2 supports sRGB, greyscale, YCC or a space described by an ICC profile, written here as 8-bit sRGB.
Transparency: the PNG stores it as a full alpha channel, so edges and shadows can fade smoothly; the JP2 keeps it as an extra component flagged as opacity.
Metadata: the PNG can carry text chunks, an ICC profile, physical resolution and EXIF in an eXIf chunk; JP2 can carry XML, ICC and resolution boxes, but nothing is copied across.
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.
PNG files usually come from screenshots, design exports, logos and web graphics.
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.
When converting PNG to JP2 makes sense
JP2 is the better choice for archival masters and specialist imaging, while PNG suits screenshots, logos, graphics and anything that needs transparency.
JP2 strengths: True lossless mode; High bit depths and very large images; Standardised for archives and digital cinema. Drawbacks to weigh: Browsers do not display it; Slow to encode and decode; Patchy support in everyday apps.
Limitations
- Lossless JPEG 2000 is larger than a lossy one, but usually smaller than an uncompressed TIFF of the same pixels.
- No current browser displays JP2 by default; archive and imaging software opens it.
More conversions
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Frequently asked questions
Does converting PNG to JP2 lose quality?
JP2 is written losslessly, so the pixels are stored exactly as decoded. 16-bit PNGs from photo and scientific software are reduced to 8 bits per channel.
Is transparency kept in the JP2?
Yes. PNG stores it as a full alpha channel, so edges and shadows can fade smoothly, and the JP2 is written with an alpha channel, so transparent areas stay transparent.
Is the JPEG 2000 file lossless?
Yes. It is written with JPEG 2000's reversible 5/3 wavelet, so decoding it gives back exactly the pixels that went in. The trade-off is size: a lossless JP2 is larger than a lossy one, though usually smaller than an uncompressed TIFF.
Which apps open JP2 files?
MacOS Preview, GIMP, IrfanView, XnView, ImageMagick and the OpenJPEG tools. It does not open in web browsers by default.
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.