[jepjepjep]

I have thousands of jpegs that should be in portrait orientation. I am switching to either Lightroom or Aperture, but neither is capable of doing lossless rotation.

Therefore, I am looking for a program that allows me to do lossless rotation before importing the pictures to Aperture/Lightroom. It should:
- work on Mac Os X Lion,
- be free of charge,
- rotate jpgs losslessly,
- fix the thumbnail,
- remove the auto-rotate tag (all of my cameras had auto-rotate tagging on),
- switch the pixel numbers (width x length) accordingly,
- and leave all other exif -data untouched.
- I would also prefer to stay away from the command line.

So far I have tried Xee, Cheese, and XnviewMP. They either did not launch or created files that were roughly 10% smaller than the original (which I believe means that the rotation was not lossless after all). I never changed any settings on the programs and I only tried jpegs with dimensions that are divisible by 16.

Can you advise how to fix the problem with aforementioned programs?

Alternatively, I would gladly accept recommendations for other programs, however, I have also quickly checked the following programs:
- PhotoToolCM
- Jpegtran
- Imagemagick
- Cocoviewx
- Image capture
- Nconvert
All of them seemed to either not be available for Lion or require the use of command line.

Thank you in advance!
- jepjepjep

[boriscleto]

Preview not saving JPG rotation? Use Exif data to fix rotated image display

I'm pretty sure GraphicConverter does lossless rotation.

BTW, all editing in Aperture "lossless". No changes are made to a file until you export it. Lightroom works the same way.

[RioRico]

I've used XnView on WinDoze machines for many years, and its JPG rotations are indeed lossless in terms of IQ. The difference in file size is because original JPGs may contain 'waste' bytes. Back when storage was more expensive, I'd run some app that snipped wasted space from JPGs without causing any loss in IQ. Savng 5-10% on a few thousand JPGs can make a difference when each megabyte is fairly costly.

How to tell if a rotation is lossy: Perform it over and over. So, use XnView or whatever to right-rotate an image 90 degrees many times. Let's say it's Img0001.jpg. Make a copy called Img0001a.jpg. Spin it 90 degrees. And again, and again, and again, 25 times or whatever. Now compare the original Img0001.jpg with the modified Img0001a.jpg. If the latter is fuzzier, the rotation was lossy. If they're the same, it's lossless. Try it and see.

[mole]

Irfanview does lossless rotating, as well as many other simple manipulations. It's written for windows, but will work just fine on mac using Winebottler:

Wine Builds - Run Windows Programs directly on OS X

When you start up winebottler, one of the options under "install predefined prefixes" is Irfanview.

[calsan]

Xee can do it.