14.7. Creating and Formatting New Images or Devices
			Create the new disk image filename of size 
size and format format.
		qemu-img create [-f format] [-o options] filename [size]
# qemu-img create [-f format] [-o options] filename [size]
			If a base image is specified with 
-o backing_file=filename, the image will only record differences between itself and the base image. The backing file will not be modified unless you use the commit command. No size needs to be specified in this case.