fix a broken link and minor update doc example (#425)

* fix a broken link.

* fix a broken link.

* fix a broken link.

* add placeholder for easy example reference.

Author: arisliang

tensorlayer/layers/convolution.py

@@ -497,7 +497,7 @@ def __init__(
 
 
 class UpSampling2dLayer(Layer):
-    """The :class:`UpSampling2dLayer` class is a up-sampling 2D layer, see `tf.image.resize_images <https://www.tensorflow.org/versions/master/api_docs/python/image/resizing#resize_images>`__.
+    """The :class:`UpSampling2dLayer` class is a up-sampling 2D layer, see `tf.image.resize_images <https://www.tensorflow.org/api_docs/python/tf/image/resize_images>`__.
 
     Parameters
     ----------
@@ -1369,6 +1369,7 @@ def conv2d(
 
     Examples
     --------
+    >>> x = tf.placeholder(tf.float32, shape=(None, 28, 28, 1))
     >>> net = InputLayer(x, name='inputs')
     >>> net = Conv2d(net, 64, (3, 3), act=tf.nn.relu, name='conv1_1')
     >>> net = Conv2d(net, 64, (3, 3), act=tf.nn.relu, name='conv1_2')

tensorlayer/layers/extend.py

@@ -13,7 +13,7 @@
 class ExpandDimsLayer(Layer):
     """
     The :class:`ExpandDimsLayer` class inserts a dimension of 1 into a tensor's shape,
-    see `tf.expand_dims() <https://www.tensorflow.org/api_docs/python/array_ops/shapes_and_shaping#expand_dims>`__ .
+    see `tf.expand_dims() <https://www.tensorflow.org/api_docs/python/tf/expand_dims>`__ .
 
     Parameters
     ----------
@@ -57,7 +57,7 @@ def __init__(
 class TileLayer(Layer):
     """
     The :class:`TileLayer` class constructs a tensor by tiling a given tensor,
-    see `tf.tile() <https://www.tensorflow.org/api_docs/python/array_ops/slicing_and_joining#tile>`__ .
+    see `tf.tile() <https://www.tensorflow.org/api_docs/python/tf/tile>`__ .
 
     Parameters
     ----------