How to crop an image using ImageMagick from the command line?

Question

I am trying to crop a 640x640 image using ImageMagick on the command line.

I need to remove about 20 pixels from the bottom part of the image all the way from left to right. A long strip along the bottom.

I know about the shave command.

What would be the command to enter in the command line? I am using the Windows version of this software.

Answer 1

Assuming that you always know the size of your image you can do it like this:

convert original.jpg -crop 640x620+0+0 cropped.jpg

With the -crop operator you specify the size of the cut out image and the offset from the upper left corner of the old image. In order to get rid of the 20px along the bottom, you have to choose a size of 640x620 and an offset of 0+0

Answer 2

Use ImageMagick's -chop operator as follows to remove 20 rows of pixels from the bottom:

convert image.png -gravity South -chop 0x20 result.png

Change to -gravity North to chop top 20 rows.

---

Change to:

convert image.png -gravity East -chop 20x0 result.png

to crop from right side, note that the 20 pixels are now before the x separator.

Answer 3

Actually it took me a wile to get this right, so I thought let's post it here.

"C:\Program Files\ImageMagick-7.0.10-Q8\magick" convert -crop 100x100+800+600 fileIn.png fileOut.png

so one need both "magick","convert" without "-" and then the options with "-". The history of this strange call is that convert used to be an executable (The only executable is magick). However since there was another windows system program with the same name "convert", it's now passed as an argument somehow. Moreover one needs to have the folder in path.

An easy batch to simplify the call could be:

crop fileIn.png fileOut.png 100,100,800,600

where the code would be

crop.bat

set fname1=%1
set fname2=%2
set x0=%3
set y0=%4
set w=%5
set h=%6
"C:\Program Files\ImageMagick-7.0.10-Q8\magick" convert -crop %w%x%h%+%x0%+%y0% %fname1% %fname2%

Answer 4

• Crop centered in batches

  for f in *.jpg; do convert "$f" -gravity center -crop 98x98+0+0 +repage "$f" ; done
  

• Fulfil with -extent in a canvas -background white

  for f in *.jpg; do convert "$f" -gravity center -crop 98x98+0+0 +repage -extent 98x98 -background white "$f" ; done