[docker] Where are Docker images stored on the host machine?

On the newly released 'Docker for Windows', which uses Hyper-V, data is located in the Docker virtual hard disk:

C:\Users\Public\Documents\Hyper-V\Virtual hard disks\MobyLinuxVM.vhdx

You can also open the 'Hyper-V Manager' for access to the Docker / MobyLinuxVM.