qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2
Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB
-b the source/base image
-f format is qcow2 and the location of the destination image
What is so special about this? It's even quicker than creating a template with OpenVZ but this is an actual OS.
It saves time a........