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ImageMagick Identify Command-line Tool

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 70x46 70x46+0+0 8-bit sRGB 2.36KB 0.000u 0:00.000

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) Mime type: image/jpeg Class: DirectClass Geometry: 70x46+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: 3220 Red: min: 35 (0.137255) max: 255 (1) mean: 145.57 (0.570865) standard deviation: 67.2976 (0.263912) kurtosis: -1.37971 skewness: 0.0942169 entropy: 0.974889 Green: min: 33 (0.129412) max: 255 (1) mean: 89.2193 (0.349879) standard deviation: 52.0803 (0.204236) kurtosis: 2.70722 skewness: 1.82562 entropy: 0.877139 Blue: min: 11 (0.0431373) max: 255 (1) mean: 80.3742 (0.315193) standard deviation: 53.8536 (0.21119) kurtosis: 2.90978 skewness: 1.92617 entropy: 0.866692 Image statistics: Overall: min: 11 (0.0431373) max: 255 (1) mean: 105.055 (0.411979) standard deviation: 58.1422 (0.228008) kurtosis: 1.25759 skewness: 1.4277 entropy: 0.90624 Rendering intent: Perceptual Gamma: 0.454545 Chromaticity: 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: 70x46+0+0 Dispose: Undefined Iterations: 0 Compression: JPEG Quality: 92 Orientation: Undefined Properties: date:create: 2014-11-09T09:00:35-05:00 date:modify: 2014-11-09T09:00:35-05:00 jpeg:colorspace: 2 jpeg:sampling-factor: 2x2,1x1,1x1 signature: 22a99838bd5594250f706d1d9383b2830f439fcbaf1455cbe2f7f59a4deb065a Artifacts: filename: rose.jpg verbose: true Tainted: False Filesize: 2.36KB Number pixels: 3.22K Pixels per second: 3.22EB User time: 0.000u Elapsed time: 0:01.000 Version: ImageMagick Q16

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
image.raw RGB 640x480 sRGB 9kb 0.000u 0:01

Here we display the image texture features, moments, perceptual hash, and the number of unique colors in the image:

-> identify -verbose -features 1 -moments -unique image.png

Here is a special define that outputs the location of the minimum or maximum pixel of the image:

identify -precision 5 -define identify:locate=maximum -define identify:limit=3 image.png

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 on, activate, off, deactivate, set, opaque, copy", transparent, extract, background, or shape the alpha channel
-antialias remove pixel-aliasing
-authenticate value decrypt image with this password
-channel type apply option to select image channels
-clip clip along the first path from the 8BIM profile
-clip-mask filename associate clip mask with the image
-clip-path id clip along a named path from the 8BIM profile
-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
-endian type endianness (MSB or LSB) of the image
-extract geometry extract area from image
-features distance analyze image features (e.g. contract, correlations, etc.).
-format string output formatted image characteristics
-gamma value level of gamma correction
-grayscale method convert image to grayscale
-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
-mask filename associate a mask with the image
-moments display image moments and perceptual hash.
-monitor monitor progress
-negate replace each pixel with its complementary color
-precision value set the maximum number of significant digits to be printed
-quiet suppress all warning messages
-regard-warnings pay attention to warning messages.
-respect-parentheses 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
-unique display image the number of unique colors in the image.
-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