• View Image Metadata on Linux

    From Black Panther@CRBBSNET to All on Tue Aug 27 14:23:02 2019
    How To View Image Metadata On Linux

    by sk - Published August 26, 2019 - Updated August 27, 2019

    Image Metadata is a set of information about the images. Metadata is either embedded into the image itself or stored in a separate file. There are three types of Metadata, namely;

    Technical metadata,
    Descriptive metadata,
    Administrative metadata.

    As the name says, the Technical metadata usually includes technical information of an image, such as camera details, DPI, shutter speed, file size, image format, the date and time when the image is captured or created, the software used to create the image and a few other details. The technical metadata is mostly generated automatically by the camera devices.

    The Descriptive metadata is manually added by the photographer. The owner (or photographer) can add it manually by using any external software such as GIMP or Photoshop. It includes the information such as the title of the photo, location, photographer name and comments etc. The descriptive metadata is very useful to search photos easily and quickly.

    The Administrative metadata contains identification and contact details of the owner, license, copyright and usage terms of the images.

    Adding metadata to images is important to prevent content theft, misuse and track the usage of images. However, the metadata can be easily striped away. Hope you get the basic idea about Image metadata and its types.

    Now let us go ahead and see how to find the information about images from command line on Linux.

    View Image Metadata On Linux

    There are many tools to find the metadata of an image on Linux. Here, I have given three command line tools to view such details.

    1. Using ImageMagick

    ImageMagick has a command line tool named "Identify" to find image metadata. ImageMagick is available in the default repositories of most Linux distributions.

    On Arch Linux and its variants, run the following command to install ImageMagick:

    $ sudo pacman -S imagemagick

    On Debian, Ubuntu, Linux Mint:

    $ sudo apt install imagemagick

    On Fedora:

    $ sudo dnf install imagemagick

    On SUSE/openSUSE:

    $ sudo zypper install ImageMagick

    Now let us find Image metadata. To do so, simply run:

    $ identify -verbose image.png

    This command will list detailed output of the metadata of the given image.

    Image: image.png
    Format: PNG (Portable Network Graphics)
    Mime type: image/png
    Class: DirectClass
    Geometry: 1366x768+0+0
    Units: Undefined
    Type: TrueColor
    Endianess: Undefined
    Colorspace: sRGB
    Depth: 8-bit
    Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
    Channel statistics:
    Pixels: 1049088
    min: 0 (0)
    max: 255 (1)
    mean: 158.62 (0.62204)
    standard deviation: 36.8176 (0.144383)
    kurtosis: -0.256842
    skewness: -0.00384146
    entropy: 0.897097
    min: 0 (0)
    max: 255 (1)
    mean: 39.1664 (0.153594)
    standard deviation: 30.5192 (0.119683)
    kurtosis: 26.7374
    skewness: 4.16992
    entropy: 0.773393
    min: 0 (0)
    max: 255 (1)
    mean: 48.4269 (0.189909)
    standard deviation: 27.7343 (0.108762)
    kurtosis: 33.5882
    skewness: 4.85108
    entropy: 0.741411
    Image statistics:
    min: 0 (0)
    max: 255 (1)
    mean: 82.0712 (0.321848)
    standard deviation: 31.9173 (0.125166)
    kurtosis: 35.6513
    skewness: 6.83895
    entropy: 0.803967
    Rendering intent: Perceptual
    Gamma: 0.454545
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
    Background color: white
    Border color: srgb(223,223,223)
    Matte color: grey74
    Transparent color: black
    Interlace: None
    Intensity: Undefined
    Compose: Over
    Page geometry: 1366x768+0+0
    Dispose: Undefined
    Iterations: 0
    Compression: Zip
    Orientation: Undefined
    date:create: 2019-08-26T19:25:54+06:00
    date:modify: 2019-08-09T13:49:32+05:00
    png:IHDR.bit-depth-orig: 8
    png:IHDR.bit_depth: 8
    png:IHDR.color-type-orig: 2
    png:IHDR.color_type: 2 (Truecolor)
    png:IHDR.interlace_method: 0 (Not interlaced)
    png:IHDR.width,height: 1366, 768
    png:sRGB: intent=0 (Perceptual Intent)
    filename: image.png
    verbose: true
    Tainted: False
    Filesize: 379KB
    Number pixels: 1.049M
    Pixels per second: 26.23MB
    User time: 0.040u
    Elapsed time: 0:01.039
    Version: ImageMagick 6.9.7-4 Q16 x86_64 20170114 http://www.imagemagick.org

    If you only want the basic details, such as simply remove -verbose option.

    $ identify image.png
    image.png PNG 1366x768 1366x768+0+0 8-bit sRGB 379KB 0.000u 0:00.000

    More details can be found in the man pages:

    $ man identify

    2. Using file command

    We can use file command, which is used to determine file types, to view metadata of an image.

    $ file image.png
    image.png: PNG image data, 1366 x 768, 8-bit/color RGB, non-interlaced

    The file command doesn’t have an option to provide detailed output like "identify" command. It only prints the basic metadata.

    Read man pages to know more about file command:

    $ man file

    3. Using Exif Tool

    Exif is a command line utility to display and change EXIF data of an image. For those wondering, EXIF (stands for Exchangeable Image File Format) is typically a JPEG file written in your storage device whenever you take a
    photo with your smartphone or camera. EXIF data includes details such as date and time of photos, camera settings, geolocation, license and copyright information etc. It is available in the default repositories in Debian and its derivatives like Ubuntu.

    $ sudo apt install exif

    To view Image metadata using exif, simply run:

    $ exif image.jpg

    Exif will produce a nice output in tabular column format like below.

    EXIF tags in 'image.jpg' ('Motorola' byte order): --------------------+---------------------------------------------------------- Tag |Value --------------------+---------------------------------------------------------- Image Description |Lady Evelyn Falls/Chutes Lady Evelyn, Northwest Territori Artist |J. A. Kraulis
    Copyright |J. A. Kraulis/Masterfile (Photographer) - [None] (Editor) XP Title |Lady Evelyn Falls/Chutes Lady Evelyn, Northwest Territori XP Author |J. A. Kraulis
    Padding |2060 bytes undefined data
    X-Resolution |72
    Y-Resolution |72
    Resolution Unit |Inch
    Padding |2060 bytes undefined data
    Exif Version |Exif Version 2.1
    FlashPixVersion |FlashPix Version 1.0
    Color Space |Internal error (unknown value 65535) --------------------+----------------------------------------------------------

    Exif not only reads the metadata but also writes EXIF to the images. For more details, check man pages:

    $ man exif

    Hope this helps.


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