writing
    directories.  In normal use there is no need to explicitly
    read or write a directory: the library automatically reads the first
    directory in a file when opened for reading, and directory information
    to be written is automatically accumulated and written when writing
    (assuming <tt>TIFFClose</tt> or <tt>TIFFFlush</tt> are called).
  </p>
  <p>
    For a file open for reading the <tt>TIFFSetDirectory</tt> routine can
    be used to select an arbitrary directory; directories are refe