title: Python write / add image data by appending to Multipage TIFF file using tifffile
body: <p>I would like to add image data (a numpy matrix) to an already existing Multipage TIFF file using the tifffile module from Christoph Gohlke: <a href="http://www.lfd.uci.edu/~gohlke/code/tifffile.py.html" rel="nofollow noreferrer">http://www.lfd.uci.edu/~gohlke/code/tifffile.py.html</a></p>
  
  <p>And I would like to do it without having to load the whole file because it can be a heavy one (long fluorescence microscopy experiments...).
  On this page: <a href="https://github.com/scienceopen/pyimagevideo/blob/master/Demo_image_write_multipage.py" rel="nofollow noreferrer">https://github.com/scienceopen/pyimagevideo/blob/master/Demo_image_write_multipage.py</a> line 68 they say it is possible, but they just say "read the code", and I couldn't figure out how to append images doing so.
  I tried </p>
  
  <p><code>tifffile.save(ImagePath, ImageData)</code> 
  and</p>
  
  <pre><code>with tifffile.TiffWriter(ImagePath) as tif2write:
      tif2write.save(ImageData)
  </code></pre>
  
  <p>but I doesn't append data, it overwrites the file.</p>