Conversion always results in a left/right flip. Also, mri_convert complains that no .mat file is available but there are no mat files provided...
mri_convert S01.native.mri.img S01.native.mri.nii.gz
$Id: mri_convert.c,v 1.179.2.2 2011/05/16 20:53:47 greve Exp $
reading from S01.native.mri.img...
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INFO: could not find /Users/Januz/Downloads/__Tests/__test/S01.native.mri.mat file for direction cosine info.
INFO: use Analyze 7.5 hdr->hist.orient value: 0, transverse unflipped (default).
INFO: if not valid, please provide the information in /Users/Januz/Downloads/__Tests/__test/S01.native.mri.mat file
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TR=0.00, TE=0.00, TI=0.00, flip angle=0.00
i_ras = (-1, 0, 0)
j_ras = (0, 1, 0)
k_ras = (0, 0, 1)
writing to S01.native.mri.nii.gz...