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ImageFileApply—Wolfram Documentation

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ImageFileApply[f,inputfile,outputfile]

applies the function f to the list of channel values for each pixel of the image stored in inputfile and stores the result in outputfile.

Details and Options
Details and Options Details and Options
Examples  
Basic Examples  
Options  
Interleaving  
Method  
Applications  
See Also
Related Guides
History
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ImageFileApply

ImageFileApply[f,inputfile,outputfile]

applies the function f to the list of channel values for each pixel of the image stored in inputfile and stores the result in outputfile.

Details and Options

  • ImageFileApply can be used to read, process, and write successive blocks of data from a very large image file whose size could exceed available memory.
  • ImageFileApply[f,inputfile] stores the result under the "Image" directory in $WolframDocumentsDirectory.
  • ImageFileApply works with TIFF, JPEG, and PNG files. The created outputfile always has the same file format, data type, and dimensions as inputfile.
  • ImageFileApply works on images with any number of channels.
  • The image files inputfile and outputfile can be given as a string or a File object.
  • The function f should always return a number or a list of any length.
  • The channel values supplied to f are normally in the range 0 to 1, regardless of the underlying type used in the Image object. The function f is assumed to return channel values that are normally in the range 0 to 1.
  • The following options can be given:
  • Interleaving Truewhether to supply f lists of channel values
    Method Automaticmethod to use
  • The following suboptions can be given to Method:
  • "ImageList"Allframes to process from a multi-frame file
    "MaxBlockSize"8000000maximal size of image blocks in pixels loaded into the memory
  • For the most efficient file processing, stripes or tiles of the image may be accessed in a specific order.
  • The value of the option "MaxBlockSize" may be exceeded if it is smaller than the smallest block supported for the input file.
  • With "ImageList"->{l1,l2,…}, the output image only contains the processed frames.

Examples

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Basic Examples  (2)

Out-of-core negation of a JPEG file:

Wolfram Language code: file = ImageFileApply[1 - #&, ExampleData[{"TestImage", "Apples"}, "FilePath"]]

Import a thumbnail of the result:

Wolfram Language code: Thumbnail[%]

Specify the output file name:

Wolfram Language code: ImageFileApply[Mean, ExampleData[{"TestImage", "Flower"}, "FilePath"], "ImageFileApply-example.jpeg"]

Options  (3)

Interleaving  (1)

Use Interleaving->False when the function has to be applied to each channel separately:

Wolfram Language code: f[x_Real] := Piecewise[{{2x, x <= .5}, {2 - 2x, x > .5}}]; ImageFileApply[f, ExampleData[{"TestImage", "RadcliffeCamera"}, "FilePath"], Interleaving -> False]

Import the resulting image:

Wolfram Language code: Thumbnail[%]

Method  (2)

Apply the function to only one frame of a multi-image file using "ImageList":

Wolfram Language code: path = ExampleData[{"TestImage3D", "Orbits"}, "FilePath"];
Wolfram Language code: Import@ImageFileApply[1 - #&, path, Method -> {"ImageList" -> 50}]

Apply the function to a list of frames:

Wolfram Language code: Import@ImageFileApply[1 - #&, path, Method -> {"ImageList" -> {50, 60}}]

Choosing an appropriate value of "MaxBlockSize" may significantly improve the performance:

Wolfram Language code: path = ExampleData[{"TestImage", "Marruecos"}, "FilePath"];
Wolfram Language code: Table[ AbsoluteTiming[ImageFileApply[# ^ 2&, path, Method -> {"MaxBlockSize" -> size}];]//First, {size, {1000000, 8000000}}]

Applications  (2)

Out-of-core binarize a single channel image:

Wolfram Language code: ImageFileApply[Boole[# < 0.7]&, ExampleData[{"TestImage", "ResolutionChart"}, "FilePath"]]

Thumbnail of the resulting image:

Wolfram Language code: Thumbnail[%]

Create a darker version of an image:

Wolfram Language code: ImageFileApply[0.5#&, ExampleData[{"TestImage", "Boat"}, "FilePath"]]

Thumbnail of the resulting image:

Wolfram Language code: Thumbnail[%]
Wolfram Research (2012), ImageFileApply, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageFileApply.html (updated 2020).

Text

Wolfram Research (2012), ImageFileApply, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageFileApply.html (updated 2020).

CMS

Wolfram Language. 2012. "ImageFileApply." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/ImageFileApply.html.

APA

Wolfram Language. (2012). ImageFileApply. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ImageFileApply.html

BibTeX

@misc{reference.wolfram_2026_imagefileapply, author="Wolfram Research", title="{ImageFileApply}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/ImageFileApply.html}", note=[Accessed: 14-November-2026]}

BibLaTeX

@online{reference.wolfram_2026_imagefileapply, organization={Wolfram Research}, title={ImageFileApply}, year={2020}, url={https://reference.wolfram.com/language/ref/ImageFileApply.html}, note=[Accessed: 14-November-2026]}