Add 'viewer' to the list of possible values that shouldn't be considered as images.
Add 'viewer' to the list of possible values that shouldn't be considered as images.



Former-commit-id: f34e18a75345cabfdd952675a3e6d1e1f2d3e0a7
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox