Image Format and Characteristics
Example Usage • Option Summary
The magick 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 magick identify command or see below for example usages of the command.
Example Usage
We list a few examples of the magick identify command here to illustrate its usefulness and ease of use. To get started, lets identify an image in the JPEG format:
-> magick identify rose.jpg
rose.jpg JPEG 70x46 70x46+0+0 8-bit sRGB 2.36KB 0.000u 0:00.000
By default, magick identify provides the following output:
Filename[frame #] image-format widthxheight page-widthxpage-height+x-offset+y-offset colorspace user-time elapsed-timeNext, we look at the same image in greater detail:
-> magick identify -verbose rose.jpg
Image: rose.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Mime type: images/jpeg
Class: DirectClass
Geometry: 70x46+0+0
Units: Undefined
Type: TrueColor
Endianness: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
Red: 8-bit
Green: 8-bit
Blue: 8-bit
Channel statistics:
Pixels: 3220
Red:
min: 31 (0.121569)
max: 255 (1)
mean: 145.557 (0.570814)
standard deviation: 69.1933 (0.271346)
kurtosis: -1.38945
skewness: 0.138955
entropy: 0.970683
Green:
min: 27 (0.105882)
max: 255 (1)
mean: 89.246 (0.349984)
standard deviation: 52.4608 (0.205729)
kurtosis: 2.60139
skewness: 1.80708
entropy: 0.869711
Blue:
min: 21 (0.0823529)
max: 255 (1)
mean: 80.4196 (0.315371)
standard deviation: 54.9377 (0.215442)
kurtosis: 2.93417
skewness: 1.95544
entropy: 0.853176
Image statistics:
Overall:
min: 21 (0.0823529)
max: 255 (1)
mean: 105.074 (0.412056)
standard deviation: 58.8639 (0.230839)
kurtosis: 1.37788
skewness: 1.48073
entropy: 0.897856
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)
Alpha color: grey74
Background color: white
Border color: srgb(223,223,223)
Transparent color: none
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 70x46+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Quality: 92
Orientation: Undefined
Properties:
jpeg:colorspace: 2
jpeg:sampling-factor: 1x1,1x1,1x1
signature: aea65c9b557d779d142f26d04abe7008bab50f1e9647faae20afdcc6c15140d5
Artifacts:
verbose: true
Tainted: False
Filesize: 2.65KB
Number pixels: 3.22K
User time: 0.000u
Elapsed time: 0:01.000
Version: ImageMagick 7.0.4-8 Q16 x86_64 http://imagemagick.org
Note, the image signature is generated from the pixel components, not the image metadata.
To get the print size in inches of an image at 72 DPI, use:
-> magick 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:
-> magick 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:
-> magick identify -verbose -features 1 -moments -unique image.pngTo display the convex hull and minimum bounding box attributes of the image, use:
magick identify -define identify:convex-hull=true image.pngHere is a special define that outputs the location of the minimum or maximum pixel of the image:
magick identify -precision 5 -define identify:locate=maximum -define identify:limit=3 image.pngYou can find additional examples of using magick identify in Examples of ImageMagick Usage.
Option Summary
The magick 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 |
| -ping | by default, efficiently determine certain image characteristics. |
| -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 |