diff --git a/docker/utils/decorators.py b/docker/utils/decorators.py
index 6f438249..1ed0b6a0 100644
--- a/docker/utils/decorators.py
+++ b/docker/utils/decorators.py
@@ -3,11 +3,14 @@ from .. import errors
 
 def check_resource(f):
     def wrapped(self, resource_id=None, *args, **kwargs):
-        if resource_id is None and (
-            kwargs.get('container') is None and kwargs.get('image') is None
-        ):
-            raise errors.NullResource(
-                'image or container param is None'
-            )
+        if resource_id is None:
+            if kwargs.get('container'):
+                resource_id = kwargs.pop('container')
+            elif kwargs.get('image'):
+                resource_id = kwargs.pop('image')
+            else:
+                raise errors.NullResource(
+                    'image or container param is undefined'
+                )
         return f(self, resource_id, *args, **kwargs)
     return wrapped
diff --git a/docker/version.py b/docker/version.py
index 4cec7446..7d51a51a 100644
--- a/docker/version.py
+++ b/docker/version.py
@@ -1,2 +1,2 @@
-version = "1.2.1-dev"
+version = "1.2.1"
 version_info = tuple([int(d) for d in version.replace("-dev", "").split(".")])
diff --git a/docs/change_log.md b/docs/change_log.md
index 54da5406..d0611593 100644
--- a/docs/change_log.md
+++ b/docs/change_log.md
@@ -1,6 +1,14 @@
 Change Log
 ==========
 
+1.2.1
+-----
+
+### Bugfixes
+
+* Fixed a bug where the check_resource decorator would break with some
+  argument-passing methods. (#573)
+
 1.2.0
 -----
 
diff --git a/tests/test.py b/tests/test.py
index d3df5c36..5d31958f 100644
--- a/tests/test.py
+++ b/tests/test.py
@@ -675,17 +675,23 @@ class DockerClientTest(Cleanup, base.BaseTestCase):
         try:
             self.client.start(container=None)
         except ValueError as e:
-            self.assertEqual(str(e), 'image or container param is None')
+            self.assertEqual(str(e), 'image or container param is undefined')
         else:
             self.fail('Command should raise ValueError')
 
         try:
             self.client.start(None)
         except ValueError as e:
-            self.assertEqual(str(e), 'image or container param is None')
+            self.assertEqual(str(e), 'image or container param is undefined')
         else:
             self.fail('Command should raise ValueError')
 
+    def test_start_container_regression_573(self):
+        try:
+            self.client.start(**{'container': fake_api.FAKE_CONTAINER_ID})
+        except Exception as e:
+            self.fail('Command should not raise exception: {0}'.format(e))
+
     def test_create_container_with_lxc_conf(self):
         try:
             self.client.create_container(