jpegtran whole directory

optimize-jpeg.sh

#! /bin/sh
 
EXTENSIONS="jpe?g"
 
if [ -z "$1" ]; then
    DIR="`pwd`"
else
    DIR="$1"
fi
 
# Optimize JPEG images
find $DIR -regextype posix-egrep -regex ".*\.($EXTENSIONS)\$" -type f | xargs -I{} jpegtran -optimize -progressive -outfile "{}.optimized" "{}"
 
# Rename xxx.jpg.optimized -> xxx.jpg
for file in $(find $DIR -name '*.optimized'); do
    chown $(stat -c "%U:%G" "${file%.optimized}") "$file"
    chmod $(stat -c "%a" "${file%.optimized}") "$file"
    mv -f "$file" "${file%.optimized}";
done

http://stackoverflow.com/questions/5579183/jpegtran-optimize-without-changing-filename