diff --git a/docker/models/images.py b/docker/models/images.py
index 32068e69..6f8f4fe2 100644
--- a/docker/models/images.py
+++ b/docker/models/images.py
@@ -30,10 +30,10 @@ class Image(Model):
         """
         The image's tags.
         """
-        return [
-            tag for tag in self.attrs.get('RepoTags', [])
-            if tag != '<none>:<none>'
-        ]
+        tags = self.attrs.get('RepoTags')
+        if tags is None:
+            tags = []
+        return [tag for tag in tags if tag != '<none>:<none>']
 
     def history(self):
         """
diff --git a/setup.py b/setup.py
index b82a74f7..9fc4ad66 100644
--- a/setup.py
+++ b/setup.py
@@ -1,10 +1,20 @@
 #!/usr/bin/env python
+from __future__ import print_function
+
 import codecs
 import os
 import sys
 
+import pip
+
 from setuptools import setup, find_packages
 
+if 'docker-py' in [x.project_name for x in pip.get_installed_distributions()]:
+    print(
+        'ERROR: "docker-py" needs to be uninstalled before installing this'
+        ' package:\npip uninstall docker-py', file=sys.stderr
+    )
+    sys.exit(1)
 
 ROOT_DIR = os.path.dirname(__file__)
 SOURCE_DIR = os.path.join(ROOT_DIR)

diff --git a/tests/unit/models_images_test.py b/tests/unit/models_images_test.py
index 392c58d7..efb21166 100644
--- a/tests/unit/models_images_test.py
+++ b/tests/unit/models_images_test.py
@@ -83,6 +83,11 @@ class ImageTest(unittest.TestCase):
         })
         assert image.tags == []
 
+        image = Image(attrs={
+            'RepoTags': None
+        })
+        assert image.tags == []
+
     def test_history(self):
         client = make_fake_client()
         image = client.images.get(FAKE_IMAGE_ID)

docker-py installation breaks docker-compose
im not quite sure if this is correct, but trying to install `docker-py` through pip after i've installed `docker-compose` breaks `docker-compose` with

```
Traceback (most recent call last):
  File "/usr/local/bin/docker-compose", line 7, in <module>
    from compose.cli.main import main
  File "/usr/local/lib/python2.7/site-packages/compose/cli/main.py", line 20, in <module>
    from ..bundle import get_image_digests
  File "/usr/local/lib/python2.7/site-packages/compose/bundle.py", line 13, in <module>
    from .network import get_network_defs_for_service
  File "/usr/local/lib/python2.7/site-packages/compose/network.py", line 7, in <module>
    from docker.types import IPAMConfig
ImportError: cannot import name IPAMConfig
```

To fix that error, i just need to do the installations in this order:
```
pip install docker-py
pip install docker-compose
```


gist:
https://gist.github.com/serialdoom/3a443c420aa29f9422f8c5fc73f46602

python/pip versions tried:
```
docker run -it python:2.7.13 bash -c 'pip --version'
pip 9.0.1 from /usr/local/lib/python2.7/site-packages (python 2.7)
docker run -it python:2.7.12 bash -c 'pip --version'
pip 8.1.2 from /usr/local/lib/python2.7/site-packages (python 2.7)
```
tests/unit/models_images_test.py::ImageTest::test_tags
tests/unit/models_images_test.py::ImageCollectionTest::test_build tests/unit/models_images_test.py::ImageCollectionTest::test_get tests/unit/models_images_test.py::ImageCollectionTest::test_list tests/unit/models_images_test.py::ImageCollectionTest::test_load tests/unit/models_images_test.py::ImageCollectionTest::test_pull tests/unit/models_images_test.py::ImageCollectionTest::test_push tests/unit/models_images_test.py::ImageCollectionTest::test_remove tests/unit/models_images_test.py::ImageCollectionTest::test_search tests/unit/models_images_test.py::ImageTest::test_history tests/unit/models_images_test.py::ImageTest::test_save tests/unit/models_images_test.py::ImageTest::test_short_id tests/unit/models_images_test.py::ImageTest::test_tag