The article shows how to perform images batch resize using Imagemagick CLI.
Install Imagemagick:
apt-get install imagemagick
Resize to 50% of original image size in a batch:
for file in `ls -1 *.jpeg`; do convert ${file} -resize 50% Resize_${file}; done
Resize to certain size in a batch:
for file in `ls -1 *.jpeg`; do convert ${file} -resize 1024x768 Resize_${file}; done