JPG to JP2 Converter
Convert JPG to JP2 in your browser. JPG files usually come from cameras, phones, scanners and almost every app that saves photos; 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
JPG expected · other image formats also work
How to use JPG to JP2
- 1
Add your JPG 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 jpg to jp2
Where the JP2 goes next
JP2 opens in macOS Preview, GIMP, IrfanView, XnView, ImageMagick and the OpenJPEG tools.
JP2 next to JPG
The JP2 keeps the decoded pixels without lossy compression, so expect it to be larger than the JPG.
No new artefacts
JPG is already lossy, since it stores lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; the JP2 keeps the decoded pixels losslessly, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JPG vs JP2
What changes from JPG to JP2
Encoding: the JPG uses lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; 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: 8 bits per channel in the JPG; JP2 allows up to 16 bits per channel is common, more is possible, and the JP2 written here has 8 bits per channel.
Colour: YCbCr shown as RGB, greyscale, or CMYK from print software in the JPG; JP2 supports sRGB, greyscale, YCC or a space described by an ICC profile, written here as 8-bit sRGB.
Metadata: the JPG can carry EXIF (camera, date, GPS), XMP, IPTC and an ICC profile in APP segments; JP2 can carry XML, ICC and resolution boxes, but nothing is copied across.
About JPG
JPEG is the universal photo format. It compresses by discarding fine detail the eye is least sensitive to, which makes photos small but blurs sharp edges and text if pushed too far.
A JPEG starts with the bytes FF D8 and is a run of marker segments: APP1 carries EXIF and often a thumbnail, APP2 an ICC profile, DQT the quantization tables that decide the quality, and SOS the compressed scan, which ends at FF D9.
JPG files usually come from cameras, phones, scanners and almost every app that saves photos.
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 JPG to JP2 makes sense
JP2 is the better choice for archival masters and specialist imaging, while JPG suits photographs that need to open anywhere.
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
- JPEG artefacts already in the file, such as blocking near edges and smeared colour, are kept as pixels: a lossless target preserves them faithfully rather than removing them.
- 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 JPG to JP2 lose quality?
JP2 is written losslessly, so the pixels are stored exactly as decoded. Artefacts already in the JPG stay, but nothing new is lost.
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.