Digikam-users Digest, Vol 241, Issue 4

[Steve Franks]

To my eye it looks as though one of the images has been rotated through
90°. That would alter the file size.
Some software rotates images, other programs take note of the rotation when
displaying the image.
I hope that makes sense,
Steve

On Wed, 4 Jun 2025 at 12:00, <digikam-users-request at kde.org> wrote:

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> Today's Topics:
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>    1. Which image to keep -- Similarity scan and different file
>       sizes (Carol C. Kankelborg)
>
>
>
> ---------- Forwarded message ----------
> From: "Carol C. Kankelborg" <cckborg2 at kankelborg.net>
> To: digikam-users at kde.org
> Cc:
> Bcc:
> Date: Tue, 3 Jun 2025 20:08:26 -0600
> Subject: Which image to keep -- Similarity scan and different file sizes
> I ran the Similarity tool with range 99–100% across my whole library. It
> detected some photos that differ in size, but it is not clear to me which
> to keep. I must have imported them directly from my camera (Nikon D5600)
> twice at different times. I moved one to an album of photos from my
> vacation and the other I left in the album it was imported into. I don’t
> understand why they would have different file sizes.
>
> The newer import file that I put into the vacation album is larger than
> the older one. I zoom in as far as I can in Preview mode and flip back and
> forth between the two photos and cannot detect a difference, suggesting the
> JPG compression is the same.
>
> Here is the result of doing an exiftool comparison between one pair of
> images. In DigiKam, it lists the Size for the larger image as 14.1 MiB
> (14,756,434) and the smaller as 12.3 MiB (12,873,885), which do not match
> the sizes from exiftool.
>
> I would rather keep the file already in the vacation album, but not if it
> has a lossier compression than the larger file. I welcome any explanation
> for what I am seeing and what the reason for the file size might be.
>
> Thanks,
> Carol
>
>
>
> Shalom-cckborg $ exiftool -diff CCK_7897.JPG ..//Camera\
> Import/2024-08-15/109D5600/CCK_7897.JPG
> ======== diff < ..//Camera Import/2024-08-15/109D5600/CCK_7897.JPG >
> CCK_7897.JPG
> < [System]        Directory                       : ..//Camera
> Import/2024-08-15/109D5600
> >                                                 : .
> < [System]        File Size                       : 15 MB
> >                                                 : 13 MB
> < [System]        File Modification Date/Time     : 2023:11:17
> 10:38:32-07:00
> >                                                 : 2023:11:19
> 17:07:02-07:00
> < [System]        File Access Date/Time           : 2025:01:18
> 04:53:40-07:00
> >                                                 : 2025:01:18
> 21:36:07-07:00
> < [System]        File Inode Change Date/Time     : 2025:01:15
> 21:31:46-07:00
> >                                                 : 2025:01:06
> 20:01:39-07:00
> < [File]          Image Width                     : 6000
> >                                                 : 4000
> < [File]          Image Height                    : 4000
> >                                                 : 6000
> < [File]          Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)
> >                                                 : YCbCr4:4:0 (1 2)
> > [File]          Current IPTC Digest             :
> 1e94c722fc098f69f3aa0d01b303732c
> < [IFD0]          Orientation                     : Rotate 90 CW
> >                                                 : Horizontal (normal)
> > [IFD0]          Processing Software             : digiKam-8.1.0
> > [IFD0]          Image Width                     : 4000
> > [IFD0]          Image Height                    : 6000
> < [ExifIFD]       Exif Image Width                : 6000
> >                                                 : 4000
> < [ExifIFD]       Exif Image Height               : 4000
> >                                                 : 6000
> < [IFD1]          Thumbnail Offset                : 18296
> >                                                 : 18284
> < [IFD1]          Thumbnail Length                : 9886
> >                                                 : 4909
> < [MPImage2]      MP Image Start                  : 13713920
> >                                                 : 13661039
> < [MPImage3]      MP Image Start                  : 13812224
> >                                                 : 13759343
> < [Composite]     Image Size                      : 6000x4000
> >                                                 : 4000x6000
> > [XMP-x]         XMP Toolkit                     : XMP Core 4.4.0-Exiv2
> > [XMP-tiff]      Image Width                     : 4000
> > [XMP-tiff]      Image Height                    : 6000
> > [XMP-tiff]      Orientation                     : Horizontal (normal)
> > [XMP-tiff]      Software                        : digiKam-8.1.0
> > [XMP-exif]      Exif Image Width                : 4000
> > [XMP-exif]      Exif Image Height               : 6000
> > [IPTC]          Originating Program             : digiKam
> > [IPTC]          Program Version                 : 8.1.0
>
>
>
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