Manipulating image files

Changing format or properties of an image file using sips (for Mac users)

Usage: sips [flags] inputFile [--out outputFile]

Image modification flags:

Flag	Meaning
-s key value	Set the value for a key (see tables below for the available profile property keys and acceptable values for each key).
-r degreesCW	Rotate an image several degrees clockwise.
-f option	Flip the image using one of the following two options: horizontal or vertical.
-c pixelsH pixelsW	Crop image to fit specified size. pixelsH indicates the new height in number of pixels, pixelsW indicates the new width in number of pixels.
-z pixelsH pixelsW	Resample image at specified size. Image aspect ratio may be altered. pixelsH indicate the new height in number of pixels, pixelsW indicate the new width in number of pixels.
-Z pixelsWH	Resample image so height and width aren't greater than specified.
--resampleWidth pixelsW	Resample image to specified width. pixelsW indicate the new width in number of pixels.
--resampleHeight pixelsH	Resample image to specified height. pixelsH indicate the new height in number of pixels.
-o	Optimize color for sharing.

If you want to modify one image to match the properties of another image (for example have one image match the height of another image), you can use the flag --getProperty with one of the following properties (which can also be used as parameters for some of the flags described above):

Profile property keys	Usage
dpiHeight	Height in dpi (printer dots per inch).
dpiWidth	Width in dpi (printer dots per inch).
pixelHeight	Height in number of pixels.
pixelWidth	Width in number of pixels.
format	Image format. Acceptable values for this key: jpeg, tiff, png, gif, jp2, pict, bmp, qtif, psd, sgi, tga, pdf.
formatOptions	Quality of the new image. Acceptable values for this key: low, normal, high, best, or some percentage.
samplesPerPixel	Samples per pixel.
bitsPerSample	Bits per sample.
software	Software use to create the image.
description	Description.
copyright	Copyright.
version	Version.
platform	Platform where file was created.
quality	Acceptable values for this key: normal, draft, best.
renderingIntent	Acceptable values for this key: perceptual, relative, saturation, absolute.
creator	Creator of the file.

For the examples below I will be using the following image, taken from the following article, which I published long time ago: link to article.

original

Convert AutismArticle1.png to pdf.

$ sips -s format pdf AutismArticle1.png --out AutismArticle1.pdf
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.pdf

Rotate AutismArticle1.png 45∘ clock-wise.

$ sips -r 45 AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/test.png

Result image:

rotated1

Rotate AutismArticle1.png 45∘ counter-clock-wise.

$ sips -r -45 AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/test2.png

Result image:

rotated2

Flip AutismArticle1.png horizontally.

$ sips -f horizontal AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/test.png

Result image:

flipped

Flip AutismArticle1.png vertically.

$ sips -f vertical AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/test.png

Result image:

flipped2

Crop AutismArticle1.png to fit a new size that be ¼th of its original height and ¼th of its original weight. The first step is to obtain the current width and height using sips with the flags --getProperty pixelWidth and --getProperty pixelHeight. Then, divide the two numbers by four. And finally use sips with the -c flag to crop the file.

$ sips --getProperty pixelHeight AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
  pixelHeight: 440
$ sips --getProperty pixelWidth AutismArticle1.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
  pixelWidth: 727
$ echo "440/4" | bc -l
110.00000000000000000000
$ echo "727/4" | bc -l
181.75000000000000000000
$ sips -c 110 181 AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
  /Users/monica/Desktop/Backup/images_presentations/test.png

Result image:

cropped

Resample image to 110x181.

$ sips -z 110 181 AutismArticle1.png --out test.png
/Users/monica/Desktop/Backup/images_presentations/AutismArticle1.png
  /Users/monica/Desktop/Backup/images_presentations/test.png
$ sips --getProperty pixelHeight test.png
/Users/monica/Desktop/Backup/images_presentations/test.png
  pixelHeight: 110
$ sips --getProperty pixelWidth test.png
/Users/monica/Desktop/Backup/images_presentations/test.png
  pixelWidth: 181

Result image:

resampled