Well, if the existing issue does not answer solve the question. I would show you something that I understand about the three things via answer the four questions.
Is Image = VHD bundled with OS.
I think it's not. The image can contain the OS disk and the data disk. So you can treat it as a thing that contains multiple VHD files. And the OS disk is the must-have for the image.
Does VHD contain OS?
No, VHD is a format of a file that contains a virtual hard disk used by Microsoft Windows Virtual PC. The hard disk can be the OS disk or the data disk, but not both.
Is Snapshot a VHD at a point of time?
Yes, the snapshot is a full, read-only copy of a virtual hard drive (VHD).
Does Snapshot contains OS as well?
Perhaps. If the snapshot is a copy of the OS disk, of course, it contains the OS disk. But if the snapshot is a copy of the data disk, then it doesn't. You can tread snapshot the same as the VHD file in a special moment.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…