EXIF information is lost on "Recompress Images" batch processing

Status changed to 'Confirmed' because the bug affects multiple users.

Same issue here.
With Gwenview I can see the shot date and time of my pictures.
After compressing them in Digikam I don't see any metadata anymore in Gwenview.

Here my config:
ii kipi-plugins 4:2.5.0-1ubuntu2 image manipulation/handling plugins for KIPI aware programs
ii kipi-plugins-common 4:2.5.0-1ubuntu2 kipi-plugins architecture-independent data
ii libkipi-data 4:4.8.3-0ubuntu0.1 data files for kipi libraries
ii libkipi8 4:4.8.3-0ubuntu0.1 library for apps that want to use kipi-plugins (runtime version)

The issue can be reproduced.

Create a Kubuntu installation USB stick with the tool usb-creator-kde and the AMD64 live CD iso.
Boot from the USB stick.
Install kipi-plugins, update related packages.
Recompress a JPEG image, the EXIF data get lost.

Config:
kubuntu@kubuntu:~$ dpkg -l | grep kipi
ii kipi-plugins 4:2.5.0-1ubuntu2 image manipulation/handling plugins for KIPI aware programs
ii kipi-plugins-common 4:2.5.0-1ubuntu2 kipi-plugins architecture-independent data
ii libkipi-data 4:4.8.3-0ubuntu0.1 data files for kipi libraries
ii libkipi8 4:4.8.3-0ubuntu0.1 library for apps that want to use kipi-plugins (runtime version)

My old system disk drive and a netbook in my living room are not affected. Both use the 32 bit version of Kubuntu 12.04.

At home I noticed that this issue is not occurring on two 4 years old installations of Kubuntu 32 bit (my old desktop and my netbook in my living room, both initially running Kubuntu 8.04 and now running 12.04).

I booted my new desktop with 32-bit Kubuntu 12.04 using the live CD on an USB stick.

After installing the same packages:
ii kipi-plugins 4:2.5.0-1ubuntu2 image manipulation/handling plugins for KIPI aware programs
ii kipi-plugins-common 4:2.5.0-1ubuntu2 kipi-plugins architecture-independent data
ii libkipi-data 4:4.8.3-0ubuntu0.1 data files for kipi libraries
ii libkipi8 4:4.8.3-0ubuntu0.1 library for apps that want to use kipi-plugins (runtime version)

I have the same issue on the 32-bit version of Kubuntu 12.04. Gwenview losses exif data on recompression.

So the issue seams to affect every fresh installation of Kubuntu 12.04, 32 and 64 bits.
For some strange reason my upgraded (32 bits) installations of Kubuntu are not affected.

It seems that Kipi uses the convert tool from ImageMagick.
I Installed the exif tool and tried to compress pictures by hand to see what happens with my exif data.
Extracting the exif information from the original picture goes fine.
After recompressing it the exif tool complains that the data is corrupt.

stephane@nausicaa:~$ exif IMG_0080.JPG > IMG_0080.exif
stephane@nausicaa:~$ convert -quality 80 IMG_0080.JPG IMG_0080_2.JPG
stephane@nausicaa:~$ exif IMG_0080_2.JPG > IMG_0080_2.exif
Données corrompues
Les données fournies ne respectent pas les spécifications.
ExifLoader: Les données fournies ne semblent pas contenir de données EXIF.

I found out why only new installations of Ubuntu are affected by this bug.

Kipi can use either graphicsmagick or imagemagick (graphicsmagick is a compatible implementation of imagemagick).
Both packages provide the command convert to recompress images.

It seems that by default Ubuntu 12.04 installs on graphicsmagick, while on older installations imagemagick was installed.

After trying found out that graphicsmagick produces corrupt exif data while imagemagick does not.

So removing graphicsmagick and installing imagemagick is a workaround for this bug.

Packages to remove:
graphicsmagick
graphicsmagick-imagemagick-compat
libgraphicsmagick3

Packages to add:
imagemagick
libmagickcore4-extra

Thanks Stéphane ! It works for me, you solved the case ;-)
Does someone can fix the packaging ?