OPT: adapt image origin given its orientation and the default orientation instead of the sign of its origin before padding
OPT: adapt image origin given its orientation and the default orientation instead of the sign of its origin before padding

3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox