Convert JPEG 2000 to ICNS on Mac
Select the JPEG 2000 files in Finder, press ⌥ F, choose ICNS and press Return. FileFlip saves each ICNS next to its original and works without an internet connection.
How to convert JPEG 2000 to ICNS with FileFlip
Select the JPEG 2000 files
In Finder or on the Desktop. One file, or a whole folder with ⌘ A.
Press ⌥ F
FileFlip opens next to the selection and lists the formats it can make from JPEG 2000. Type “ICNS” to jump to it.
Choose ICNS and press Return
The ICNS files appear next to the originals with the same names. The JPEG 2000 files stay as they are.
JPEG 2000 and ICNS
JPEG 2000 is rarely supported outside specialist software. ICNS is what macOS uses for app and folder icons.
What changes when you convert
- ICNS is lossless, so the image is saved without further loss.
- ICNS holds icon sizes up to 1024 × 1024 pixels, so a square source image of at least that size works best.
| Property | JPEG 2000 | ICNS |
|---|---|---|
| Full name | JPEG 2000 | Apple Icon Image |
| Made by | Joint Photographic Experts Group | Apple |
| Compression | Lossy or lossless (wavelet) | Usually PNG inside |
| Transparency | Yes | Yes |
| Best for | Archiving and professional imaging | Mac app, folder and file icons |
| Opens in | Preview and professional imaging tools; most browsers and many apps don’t open it | macOS; rarely anything else |
| File extension | .jp2 | .icns |
| In FileFlip | Opens and saves | Opens and saves |
Other ways on a Mac
For one file now and then you may not need FileFlip. These work with what’s already on your Mac.
Preview
Open the JPEG 2000 in Preview, choose File → Export, pick ICNS from the Format menu and click Save. If ICNS isn’t listed, hold Option while you click the Format menu. For several files, open them together, select all thumbnails in the sidebar and choose File → Export Selected Images.
Good for a few files now and then.
Terminal
The sips command converts images in place or into a new file.
sips -s format icns image.jp2 \
--out image.icnsBuilt into macOS. Use a square image; run sips --formats to check what your macOS version supports.
Questions about JPEG 2000 and ICNS
Does converting JPEG 2000 to ICNS lose quality?
ICNS is lossless, so the image is saved without further loss.
Can I convert many JPEG 2000 files at once?
Yes. Select them all in Finder, press ⌥ F and choose ICNS. Progress moves to the menu bar, so you can close the panel and keep working.
What size should the source image be?
Square, and ideally 1024 × 1024 pixels, the largest size an ICNS file holds.
Where is the ICNS file saved?
Next to the original, with the same name and the .icns extension. The JPEG 2000 file isn’t changed. In Settings you can choose a different folder instead.
Can I convert ICNS back to JPEG 2000?
Yes, FileFlip converts ICNS to JPEG 2000 as well.
Are my files uploaded anywhere?
No. FileFlip converts files on your Mac and works with the internet turned off.
Convert a whole folder of images at once
FileFlip also handles video, audio, PDFs, documents and data files. Requires macOS 14 Sonoma or later.
Coming soon for Mac