[Bash] Reduce images to send a batch of images by email for example

compress-img.bash

#!/usr/bin/env bash
#
# compress-img.bash
#
# Reduce size by 50% for each given image by copying that in 
# a new folder ./compressed.
#
# You can reduce size or quality of each image, if you don't want,
# send a link to application where there are your images. And this
# script is usless for your use case.
#
# It is very handly to send reduced images by email.
# Because often the sum of disk space for all attachments 
# to send is limited, don't be exceed 25MB for Gmail. 
# (see policies of your email service).
#
# You can archive the new set of images before 
# sending (.zip, .tar.gz ...) to reduce attachment size again.
#
# Reference:
#   https://support.google.com/mail/answer/6584?co=GENIE.Platform%3DDesktop&hl=en

# helper

height() {
    local img="$1"
    identify -ping -format '%h' "${img}"
}

width() {
    local img="$1"
    identify -ping -format '%w' "${img}"
}

size() {
    local img="$1"
    ls -lh "${img}" | awk '{print $5}'
}


# script

if [[ "${FUNCNAME[0]}" == "main" ]]; then

  cd `dirname "$0"`

  mkdir -p ./compressed/

  for img in $@; do
      convert "${img}" -resize 50% "./compressed/${img}" && \
      echo -n "./compressed/${img} created ... " && \
      size "./compressed/${img}"
  done

fi