Hi,
 
This is probably a T1 weighted anatomical image -- which are usually not acquired in the standard orientation (axial slices). MRIcron generates two additional copies of the volume, prefixed by '0', meaning that it is re-oriented to standard space, and 'co', meaning that it is additonally clipped to have an image with considerable amount of not brain volume cut out. You can use any of the three for further processing, but the re-oriented one is preferable, since many preprocessing packages assume a standard oriented image.
 
Best regards,
 
Peter