      \param z0 Starting Z-coordinates of image regions to write.
      \param c0 Starting C-coordinates of image regions to write.
    **/
    const CImgList<T>& save_cimg(const char *const filename,
                                 const unsigned int n0,
                                 const unsigned int x0, const unsigned int y0,
      \param z0 Starting Z-coordinates of image regions to write.
      \param c0 Starting C-coordinates of image regions to write.
    **/
    const CImgList<T>& save_cimg(const char *const filename,
                                 const unsigned int n0,
                                 const unsigned int x0, const unsigned int y0,