Merge pull request #33 from kohr-h/lazy_pil_import

Make PIL import lazy

tensorboardX/summary.py

@@ -38,7 +38,6 @@
 import bisect
 from six import StringIO
 from six.moves import range
-from PIL import Image
 import numpy as np
 # pylint: disable=unused-import
 from .src.summary_pb2 import Summary
@@ -164,6 +163,7 @@ def image(tag, tensor):
 
 def make_image(tensor):
     """Convert an numpy representation image to Image protobuf"""
+    from PIL import Image
     height, width, channel = tensor.shape
     image = Image.fromarray(tensor)
     import io

tensorboardX/writer.py

@@ -307,6 +307,8 @@ def add_histogram(self, tag, values, global_step=None, bins='tensorflow'):
     def add_image(self, tag, img_tensor, global_step=None):
         """Add image data to summary.
 
+        Note that this requires the ``pillow`` package.
+
         Args:
             tag (string): Data identifier
             img_tensor (torch.Tensor): Image data