mozjpeg

--Install

CentOS6:
$ yum install wget autoconf automake gcc nasm git
$ wget https://github.com/mozilla/mozjpeg/releases/download/v3.1/mozjpeg-3.2-release-source.tar.gz  
$ tar xvfz mozjpeg-3.2-release-source.tar.gz  
$ cd mozjpeg
$ ./configure
$ make
$ make install  
$ ln -s /opt/mozjpeg/bin/jpegtran /usr/bin/mozjpeg

Mageia:
$ urpmi autoconf automake libtool gcc nasm make pkg-config git
$ git clone https://github.com/mozilla/mozjpeg.git
$ cd mozjpeg
$ autoreconf -fiv
$ ./configure
$ make
$ make install
$ ln -s /opt/mozjpeg/bin/jpegtran /usr/bin/mozjpeg

--In action
$ mozjpeg -copy none -outfile /path/to/output.jpeg /path/to/input.jpeg