[libvirt-users] About .img file while creating vm

Hi, I am trying to create vm using virsh create x.xml. But I am confused as what is the .img file that is required. Here is the Disk tag from my xml. <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> * <source file='/xxx/xx_vm.img'/> * <target dev='hda'/> </disk> Is it .ova file that is converted to .img ? If anybody have links or some guide related to the topic that would be really helpful. Thank you, Amey