JPG filesize changes during import with autorotate ON

[digikam at boeziek.nl]

Hello,

I am new to Digikam and used an existing Lightroom/CaptureOne photo/filestructure with Digikam and imported those by adding a folder as a collection without any issues. Very promising app, thanks for all the hard work!

Background: I run MacOS 14.4.1 (latest) and Digikam 8.3. I shoot RAW + JPG on a Fujiflm X-T2.

Yesterday I started importing photos from an SD Card into Digikam, using "adding photos" as the USB didn't recognize my USB slot in my Thunderbolt Pro Dock.

When I select auto-rotate/flip ON, I notice that all my JPEG's are changed. Not only those that are rotated, but all of them have a new modification date in Finder.

For the rotated ones, I also noticed the file sizes are reduced. E.g. a 12.1MB JPEG on my SD card became 11MB after import on my disk or a 11.5MB became 10.4MB. So over a megabyte is trimmed, some are only reduced by 100KB.

Is that normal behaviour? Are all the JPEG's re-encoded during import? If so, doesn't that mean you start losing quality as rewriting JPGs is not recommended?

When I turn off the auto-rotate, then all files are imported unchanged.

Thanks,

Etienne