export psds of manga pages to png (save as indexed png ->remove exif tags -> pngcrush if worth it)

manga.sh

#!/bin/bash
dir="_png"
mkdir -p $dir # make diretory
for filename in *.psd; do # for all .psd files, save as indexed color .png, no transparency
	if [[ "$filename" == *"-c"* ]]; then # grayscale unless "-c" (i.e. -credits, -color) in filename
		cs="RGB"
	else
		cs="LinearGray"
	fi
	convert "$filename"[0] -colorspace $cs -colors 256 -background white -alpha remove -alpha off PNG8:$dir/"${filename%%.*}".png
done

exiftool -all= $dir/*.png # strip all exif data
rm $dir/*_original # clean up

for filename in $dir/*.png; do # pngcrush (compress) all files...
	pngcrush "$filename" "${filename%%.*}.png.crush"
	I=`stat -f "%z" "$filename"`
	J=`stat -f "%z" "${filename%%.*}.png.crush"`
	if [ $I -ge $J ]; then # ...unless resultant file isn't actually smaller
		mv "${filename%.png}.png.crush" "$filename"
	else
		rm "${filename%%.*}.png.crush"
	fi
done