Those libraries are optional. They are used to compress the images in apps sources and apk.
You have to log in via SSH to your server to install them.
Here are the commands:
For CentOS/Redhat servers:
yum install -y epel-release
yum install pngquant libjpeg optipng jpegoptim
For Ubuntu/Debian servers:
apt-get install jpegoptim optipng pngtools pngquant