optimize image files with PNGOUT

imgopti.sh

#/bin/bash
# optimize image files with PNGOUT
# usage: bash imageopti.sh dir 4

# images directory
DIR=$1
# threads
N=$2

for images in $DIR/*
do
  (
    # use 'Longest Match' strategy for fast process
    pngout -s2 "$images"
  ) &

  if [[ $(jobs -r -p | wc -l) -ge $N ]]; then
    wait -n
  fi

done

wait

# clean other file beside png
find $DIR -type f ! -name '*.png' -delete

echo "ALL DONE"