NEW: option to save an image as small as possible (voxel type choice)
NEW: option to save an image as small as possible (voxel type choice)

Former-commit-id: ba6845d7f211da72942963bb92d64c8bf890e905 [formerly 23f3c1abb4a35033fea1705205fdfb0855dbb0c6]
Former-commit-id: 5f292ecb6ad3eda28bbb9d61029dcfb8ea537243
Former-commit-id: ef8e2fe95d5615325d9084264409732bea73c65f
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox