ImageMagick is a time saver! It’s designed and extremely powerful for manipulating images with a few command lines. Few weeks ago, I had to resize a bunch of .png images and realize how helpful ImageMagick could be is such case! All I had to do was creating a short shell script very similar to the following lines:

1
2
3
4
5

mkdir img_resized
for f in *.png
do
  convert $f -resize 250x250\> img_resized/${f%.png}_250.png
done

Note that here, the size is expressed in pixels (250x250) and only images larger than 250 px are shrunk (as I use the > flag). There are many arguments and several ways of using them (e.g. you can use percentage with -resize), if you are interested in learning more, I recommend you have a look at the documentation of imageMagick. By the way, the R 📦 magick proposes a set of bindings to call ImageMagick directly from R.