To create a new image, you will need the installation CD or DVD ISO file for the guest operating system. You'll also need access to a virtualization tool. You can use KVM for this. Or, if you have a GUI desktop virtualization tool (e.g., VMWare Fusion, VirtualBox), you can use that instead and just convert the file to raw once you're done.
When you create a new virtual machine image, you will need to connect to the graphical console of the hypervisor, which acts as the virtual machine's display and allows you to interact with the guest operating system's installer using your keyboard and mouse. KVM can expose the graphical console using the VNC (Virtual Network Computing) protocol or the newer SPICE protocol. We'll use the VNC protocol here, since you're more likely to be able to find a VNC client that works on your local desktop.
