Scriptable image processing system

sips

zero-config tools
embed in macOS
easy to use

Basic Usage

cover pdf to jpg

sips -s format jpeg input.pdf --out output.jpg

# rotate 90 degrees / flip
sips -r 90 image.jpg
sips -f horizontal image.jpg
sips -f vertical image.jpg

multiple resize image with max width and height in 100 pixels

1	sips -Z 100 *.jpg