Bulk Resize Images in Ubuntu

ImageMagick Installation

sudo apt-get update
sudo apt-get install imagemagick -y

 Resize to either height or width, keeps proportions using ImageMagick

cd /path/to/output

find </path/to/images> -iname '*.jpg' -o -iname '*.png' -exec convert \{} -resize WIDTHxHEIGHT\> \{} \;