lution mosaic
  and shrink it down using mShrink to the scale desired.  This process can be costly if the
  full resolution image is not desired (or not desired yet).  It is much faster to mosaic at
  the scale of the thumbnail itself.  One reason for doing this could be to evaluate whether
  th full-resolution mosaic is worth building at all.</p>

  <p>mShrinkHdr is a simple utility that takes a FITS header template (such as might come out of
  mMakeHdr or mHdr) and make a new one at a differenc pixel scal