> I used [Homebrew] to install ImageMagick (the only OS X tool I know of where you can resize pictures on the command line)… There's the built-in command "sips

> I used [Homebrew] to install ImageMagick (the only OS X tool I know of where you can resize pictures on the command line)… There's the built-in command "sips" that comes on every Mac and has been around since at least OS X Lion (10.7). The name stands for "scriptable image processing tool", and the tool appears to use CoreGraphics to do its work. More info here: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/sips.1.html https://developer.apple.com/library/mac/documentation/Darwin...