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[Example Usage • Option Summary]

The identify program describes the format and characteristics of one or more image files. It also reports if an image is incomplete or corrupt. The information returned includes the image number, the file name, the width and height of the image, whether the image is colormapped or not, the number of colors in the image, the number of bytes in the image, the format of the image (JPEG, PNM, etc.), and finally the number of seconds it took to read and process the image. Many more attributes are available with the verbose option. See Command Line Processing for advice on how to structure your identify command or see below for example usages of the command.

Example Usage

We list a few examples of the identify command here to illustrate its usefulness and ease of use. To get started, lets identify an image in the JPEG format:

  identify rose.jpg
  rose.jpg JPEG 640x480 DirectClass 87kb 0.050u 0:01

Next, we look at the same image in greater detail:

  identify -verbose rose.jpg
  Image: rose.jpg
    Format: JPEG (Joint Photographic Experts Group JFIF format)
    Class: DirectClass
    Geometry: 70x46+0+0
    Resolution: 72x72
    Print size: 0.972222x0.638889
    Units: PixelsPerInch
    Type: TrueColor
    Endianess: Undefined
    Colorspace: RGB
    Depth: 8-bit
    Channel depth:
      red: 8-bit
      green: 8-bit
      blue: 8-bit
    Channel statistics:
      red:
        min: 37 (0.145098)
        max: 255 (1)
        mean: 145.58 (0.5709)
        standard deviation: 67.3195 (0.263998)
      green:
        min: 31 (0.121569)
        max: 255 (1)
        mean: 89.2512 (0.350005)
        standard deviation: 52.0488 (0.204113)
      blue:
        min: 17 (0.0666667)
        max: 255 (1)
        mean: 80.4075 (0.315323)
        standard deviation: 54.0052 (0.211785)
    Rendering intent: Undefined
    Interlace: None
    Background color: white
    Border color: rgb(223,223,223)
    Matte color: grey74
    Transparent color: black
    Page geometry: 70x46+0+0
    Dispose: Undefined
    Iterations: 0
    Compression: JPEG
    Quality: 100
    Orientation: Undefined
    Properties:
      create-date: 2008-01-08T11:08:52-05:00
      jpeg:colorspace: 2
      jpeg:sampling-factor: 2x2,1x1,1x1
      modify-date: 2005-04-07T12:48:13-04:00
      signature: dcd00d6303f80f4fa53f991804cb026151c1e851b7a96255e82da87299583ebc
    Artifacts:
      verbose: true
    Tainted: False
    Filesize: 3.97266kb
    Number pixels: 3.14453kb
    Version: ImageMagick 6.4.2 05/01/08 Q16 http://www.imagemagick.org

To get the print size in inches of an image at 72 DPI, use:

  identify -format "%[fx:w/72] by %[fx:h/72] inches" document.png
  8.5 x 11 inches

The depth and dimensions of a raw image must be specified on the command line:

  identify -depth 8 -size 640x480 image.raw
  mage.raw RGB 640x480 DirectClass 9kb 0.000u 0:01

You can find additional examples of using identify in Examples of ImageMagick Usage.

Option Summary

The identify command recognizes these options. Click on an option to get more details about how that option works.

Option Description
-alpha activate, deactivate, reset, or set the alpha channel
-antialias remove pixel-aliasing
-authenticate value decrypt image with this password
-channel type apply option to select image channels
-colorspace type set image colorspace
-crop geometry crop the image
-debug events display copious debugging information
-define format:option define one or more image format options
-density geometry horizontal and vertical density of the image
-depth value image depth
-extract geometry extract area from image
-format string output formatted image characteristics
-gamma value level of gamma correction
-help print program options
-interlace type type of image interlacing scheme
-interpolate method pixel color interpolation method
-limit type value pixel cache resource limit
-list type Color, Configure, Delegate, Format, Magic, Module, Resource, or Type
-log format format of debugging information
-monitor monitor progress
-quiet suppress all warning messages
-regard-warnings pay attention to warning messages.
-respect-parenthesis settings remain in effect until parenthesis boundary.
-sampling-factor geometry horizontal and vertical sampling factor
-set attribute value set an image attribute
-size geometry width and height of image
-strip strip image of all profiles and comments
-units type the units of image resolution
-verbose print detailed information about the image
-version print version information
-virtual-pixel method access method for pixels outside the boundaries of the image

To return the number of unique colors in your image, add -define identify:unique=true to your command-line