#!/bin/bash
set -a
qualities="10 50 75 85 90 95"
mkdir -p headers-pnm
for q in $qualities; do
	mkdir -p headers-$q
done
conv() {
	h=$1
	I=headers/$h.jpg
	O=headers-pnm/$h.pnm
	if [ ! -s $I ]; then
		return
	fi
	if [ $I -nt $O ]; then
		v convert $I $O
	fi
	I=$O
	for q in $qualities; do
		O=headers-$q/$h.jpg
		if [ $I -nt $O ]; then
			v cjpeg -quality $q $I > $O
		fi
	done
}
for h in $(cd headers/; ls *.jpg); do
	v conv ${h%.jpg} &
done
wait