lossless JPEG rotation

**AaronBaker** · 07-13-2008, 07:45 PM

What software are those of you that manipulate photos using for lossless JPEG rotation on a Mac? Specifically, I am looking for a good FREE minimalist program.

**stuckathuntermtn** · 07-13-2008, 07:55 PM

paint.net?

**AaronBaker** · 07-13-2008, 08:07 PM

I hear that's a decent program, but it's only available on Windows platform.

**phattypowpow** · 07-14-2008, 11:19 AM

If you have mild competence with the command line (Terminal), I highly recommend using jhead. I forget exactly where I found it on the net but it's free and kicks ass. It, like many other GUI-based programs uses jtran to do some of the heavy lifting. In addition to lossless JPG rotation, it will does other useful stuff. For example,

jhead -autorot -ta+2 -nf%Y-%m-%d-%M.S_HappyPic *.JPG

will, for all files in the directory that end in .JPG:

- rotate the pic losslessly to match the camera orientation

- adjust the time stamp forward 2 hours

- change the names of all the files in the directory to something that includes the timestamp and a useful label. This makes all your pics sort chronologically whenever you sort by name, even if you mix photos from different folders) ie:

IMG2347.JPG -> 2008-07-14-08.23_HappyPic.jpg

**Arty50** · 07-14-2008, 12:30 PM

For free, check out GIMP. It's basically opensource Photoshop for Linux/Unix.

http://www.gimp.org/

If you don't want all that power (aka. something simpler) and want a native OSX interface, I'd recommend GraphicConverter. It's $35, does quite a lot, and is a very good app. It's been around for years and the developer takes very good care of it with frequent updates.

http://www.lemkesoft.com/

**kalisto** · 07-14-2008, 08:57 PM

seashore... open source for mac.

**bio-smear** · 07-14-2008, 10:54 PM

Imagemagick from Darwinports.

convert file.jpg -rotate 90 file.jpg

What are you currently using that is not lossless?

**kalisto** · 07-14-2008, 11:56 PM

What you do mean by a 'lossless' jpeg rotation program?

The 'loss' happens when you save the file, not when you edit it...

Any app that rotates pictures should work, and if you're worried about losing quality, don't use jpeg?

**Deep Days** · 07-15-2008, 04:17 AM

Originally Posted by KaLiStO

What you do mean by a 'lossless' jpeg rotation program?

The 'loss' happens when you save the file, not when you edit it...

False. Windows Picture Editor actually degrades the resolution during rotations. Which is why I started using IrfanView (great program for batch auto-rotations per EXIF data. Only for Windows, I think, though).

**bio-smear** · 07-15-2008, 10:36 AM

You can also rotate with Preview and resave.

**spindrift** · 07-15-2008, 10:55 AM

Originally Posted by KaLiStO

What you do mean by a 'lossless' jpeg rotation program?

The 'loss' happens when you save the file, not when you edit it...

Any app that rotates pictures should work, and if you're worried about losing quality, don't use jpeg?

This thread made me actually think a bit & do a quick search.

JPEG is lossy - so if you compress, decompress, rotate, compress - you get two cycles of loss. Apparently, if the fates (or apparently in most cases, your camera) deal you the right hand, it is possible to do the rotation with the initially encoded JPEG data. Hence no second loss cycle. Fascinating...

List of apps (as of Jan) that supposedly do lossless rotation:

http://jpegclub.org/losslessapps.html

Interesting simple discussions of topic:

http://www.ammara.com/support/techno...-rotation.html
http://graphicssoft.about.com/cs/dig...atequality.htm

**kalisto** · 07-15-2008, 07:39 PM

Originally Posted by spindrift

This thread made me actually think a bit & do a quick search.

JPEG is lossy - so if you compress, decompress, rotate, compress - you get two cycles of loss. Apparently, if the fates (or apparently in most cases, your camera) deal you the right hand, it is possible to do the rotation with the initially encoded JPEG data. Hence no second loss cycle. Fascinating...

List of apps (as of Jan) that supposedly do lossless rotation:

http://jpegclub.org/losslessapps.html

Interesting simple discussions of topic:

http://www.ammara.com/support/techno...-rotation.html
http://graphicssoft.about.com/cs/dig...atequality.htm

Oh, legit.

Didn't know you could rotate without going through another cycle of loss.

I thought that was inevitable...

Question still stands, why use jpeg if you're worried that much about losing quality?

**fez** · 07-15-2008, 08:33 PM

when i first saw this thread, i wondered what the point was since jpeg is lossy. but i decided to read about it before i posted and found out there actually is lossless jpeg.

go figure.

**AaronBaker** · 07-19-2008, 04:04 PM

Originally Posted by KaLiStO

Question still stands, why use jpeg if you're worried that much about losing quality?

I rarely shoot JPEG anymore, but that does not mean that I don't have some old JPEG files from back in the day that I'd like to rotate while not loosing quality in the process. It's not like everyone one of us has always been shooting with lossless formats! I had a couple cameras from years ago where JPEG was the only capture option. So there you go, your question is no longer standing!

Thanks to everyone for your suggestions.

**AaronBaker** · 09-23-2008, 02:57 PM

I meant to post this awhile ago. . . another good, free (and easy) alternative for lossless JPEG rotation on Mac OS is with the program Xee.

http://wakaba.c3.cx/s/apps/xee.html