img.fit_to_filesize

#!/bin/bash

# Fit image to desired filesize by iteratively decrease size

: ${1?"Порядок использования: `basename $0` filename size_in_Kb [%step=5%]"}
: ${2?"Порядок использования: `basename $0` filename size_in_Kb [%step=5]"}

# Percent to step
STEP=${3:-5}
# Only digits, no %!
STEP=$( echo $STEP | sed -r 's/[^[:digit:]]*([[:digit:]]+)[^[:digit:]]*/\1/' ) # '
echo STEP=$STEP%

i=0
	while [ $( stat --format='%s' "$1" ) -gt $[ $2 * 1024 ] ]; do
	(( i++ ))
	echo "Pass $i";
	convert -resize $[ 100 - $STEP ]% "$1" - | sponge "$1"
	done

#echo "Final size is: "$[100-]"%"