// 'Imager Pixel Spacing' : defaulted to 'Pixel Spacing'
// --> This one is the *legal* one !
// FIXME : we should write it only when we are *sure* the image comes from
// 'Imager Pixel Spacing' : defaulted to 'Pixel Spacing'
// --> This one is the *legal* one !
// FIXME : we should write it only when we are *sure* the image comes from