[Digikam-users] Why does adding a keyword make the file size smaller?

[Thomas Lunde]

Hello -

Is it expected that adding a keyword should make the image's file size
smaller?  Digikam seems to have done so here.

Does anyone know what (metadata?) would have been deleted from the
original file as this tag was added?

I was surprised at this, so I tried it again and got the same result.
bottles-unchanged.jpg is a JPG image from a Panasonic DMC-FX12 digital
camera.  Other than having its filename changed, no modifications have
been done to it.  I copied the file off of the camera by inserting the
card into the SD card reader in my laptop and using a file manager to
copy it to my hard drive.

bottles.jpg is a copy of this image which was made available to
digikam.  The only thing that I (intentionally) did was to add a tag
called "bottles" after having turned on the option (Settings ->
Configure digikam -> Metadata -> IPTC Actions -> X save image tags as
"Keywords" tag) to sync the tags back to the file.

Use of strings shows that bottles.jpg has the tag and
bottles-untouched.jpg does not.  See also:

tlunde at noir:~/Desktop$ ls -asl bottles*
2188 -rwx------ 1 tlunde tlunde 2236340 2007-12-15 16:03 bottles.jpg
2200 -rwx------ 1 tlunde tlunde 2247707 2007-12-15 16:03 bottles-untouched.jpg
tlunde at noir:~/Desktop$
[Ignore the timestamps; these have been moved back and forth to
another file system via scp so the original timestamps are
unavailable.]


tlunde at noir:~/Desktop$ grep bottle bottles*
Binary file bottles.jpg matches
tlunde at noir:~/Desktop$


tlunde at noir:~$ dpkg -l |grep kam
ii  digikam                                    2:0.9.2-2ubuntu2
             digital photo management application for KDE
ii  digikam-doc                                0.9.2~beta2-1ubuntu1
             handbook for digikam and showfoto in several languages
tlunde at noir:~$

If there are packages of 0.9.3 for ubuntu gusty, I'll be happy to try
those and see if the result is the same.

Thanks for any guidance.
Thomas