Bulk Compress JPG/PNG

compress-all-images.sh

#!/bin/bash

# Setup variable extra_args with -newer argument if our tracking file exists
# Find all files with extension jpg/jpeg/png, case insensitive
# For jpg/jpeg, execute jpegoptim
# For png, execute pngquant
# Log output to compress-all-images.log


# https://stackoverflow.com/questions/38965254/jpegoptim-save-shell-last-run-and-check-files-or-folders-after-this-date
# https://unix.stackexchange.com/questions/15308/how-to-use-find-command-to-search-for-multiple-extensions
# https://unix.stackexchange.com/questions/196399/how-to-batch-resize-all-images-in-a-folder-including-subfolders
# https://stackoverflow.com/questions/19784690/when-tee-command-redirect-to-subshell-the-last-two-lines-missing
# https://stackoverflow.com/questions/229551/string-contains-in-bash

compress_images () {

	echo "Processing File: $1"

	if [[ "$1" == *".png" ]]; then
		pngquant -s 4 --skip-if-larger -Q 60-70 -f --ext .png -v "$@"
	else
		jpegoptim -m80 -o -t -v --all-progressive "$@"
	fi

	echo "End Processing"

}

export -f compress_images


extra_args=( )
[[ -e .images-last-compressed ]] && extra_args=( -newer .images-last-compressed )
{
	find ./ -type f \( -iname \*.jpg -o -iname \*.jpeg -o -iname \*.png \) "${extra_args[@]}" \
   	-exec bash -c 'compress_images "{}"' \;
} 2>&1 | awk '{ print strftime("%Y-%m-%d %H:%M:%S: " ), $0; fflush(); }' | tee -a compress-all-images.log

touch .images-last-compressed