XenDesktop 5 has two different features to provide single image management i.e., Machine Creation Services and Provisioning Services.

Machine Creation Services can only provide hosted VDI desktops (pooled or dedicated).
If we want to utilize a hosted shared desktop model, a streamed VHD model or a Hosted VDI model then we would require Provisioning Services.

MCS uses built-in technology to provide each desktop with an unique identity and also thin provisions each desktop from a master image. Only changes made to the desktop consume additional disk space

PVS uses built-in technology to provide each desktop with a unique identity, but also utilizes a complete copy of the base desktop image in read/write mode. Each copy consumes disk space, which also increases as additional items are added to the desktop image by the user.