Returned pixel array

[ZviBaratz]

Other than the general need to decode the various DICOM format encoding schemes (mosaic, multi-frame, etc.), the returned pixel array's orientation and scaling could (and possibly should) conform with dcm2niix's results.
If this were the case, NiBabel could easily also provide DICOM to NIfTI conversion. This will both encourage standardization across labs and enable users to reduce the number of different packages/tools their workflow requires.
In order to better characterize the differences in results, @matthew-brett will compare the currently returned "naive" stacked pixel arrays returned by the Series class' data property with dcm2niix's results (#70) and consider next steps to resolve #66/#67.