Hi, I am not an expert, but moving VM image is easy:
Assuming you manage your VM with new xl tool, the vm config file is located in /etc/xen/vm/ directory. My system is upgraded several times, so it may happen that you have it elsewhere, so just search for you VM name.
Now in this config file you will see specification where your image(s) is located.
Shut down your VM
Change the line in config file to whatever place you want to move your VM.
Save the config file
Move your image(s) to new location
Start the VM
This is the disk specification in VM config file:
‘format=raw, vdev=hda, access=rw, target=/var/lib/xen/images/opensuse-hvm/opensuse-hvm.raw’,