These files are original downloads of images.
 debian-testing: http://cdimage.debian.org/cdimage/openstack/testing/
 centos-7: http://cloud.centos.org/centos/7/images/
 centos-6: http://cloud.centos.org/centos/6/images/
 fedora-21: http://download.fedoraproject.org/pub/fedora/linux/releases/21/Cloud/Images/x86_64/
 fedora-26: http://download.fedoraproject.org/pub/fedora/linux/releases
freebsd-9.3: http://images.openstack.nctu.edu.tw/bsd-cloudinit/
freebsd-10.1: http://images.openstack.nctu.edu.tw/bsd-cloudinit/
 openSUSE-13.2: http://download.opensuse.org/repositories/Cloud:/Images:/openSUSE_13.2/images/
 openSUSE-Leap-42: http://download.opensuse.org/repositories/Cloud:/Images:/Leap_42.3/images/


Freebsd from openstack.nctu.edu.tw are converted with qemu-img convert for compression: qemu-img convert -O qcow2 -c input output