diff --git a/Tests/test_imageshow.py b/Tests/test_imageshow.py
index da91e35c7..244c18d91 100644
--- a/Tests/test_imageshow.py
+++ b/Tests/test_imageshow.py
@@ -14,6 +14,9 @@ class TestImageShow(PillowTestCase):
         # Test registering a viewer that is not a class
         ImageShow.register("not a class")
 
+        # Restore original state
+        ImageShow._viewers.pop()
+
     def test_show(self):
         class TestViewer:
             methodCalled = False
@@ -28,6 +31,9 @@ class TestImageShow(PillowTestCase):
         self.assertTrue(ImageShow.show(im))
         self.assertTrue(viewer.methodCalled)
 
+        # Restore original state
+        ImageShow._viewers.pop(0)
+
     def test_viewer(self):
         viewer = ImageShow.Viewer()
 
@@ -35,6 +41,10 @@ class TestImageShow(PillowTestCase):
 
         self.assertRaises(NotImplementedError, viewer.get_command, None)
 
+    def test_viewers(self):
+        for viewer in ImageShow._viewers:
+            viewer.get_command('test.jpg')
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/src/PIL/ImageShow.py b/src/PIL/ImageShow.py
index b50d61358..f1819cc5c 100644
--- a/src/PIL/ImageShow.py
+++ b/src/PIL/ImageShow.py
@@ -148,12 +148,9 @@ else:
         format = "PNG"
         options = {'compress_level': 1}
 
-        def show_file(self, file, **options):
-            command, executable = self.get_command_ex(file, **options)
-            command = "(%s %s; rm -f %s)&" % (command, quote(file),
-                                              quote(file))
-            os.system(command)
-            return 1
+        def get_command(self, file, **options):
+            command = self.get_command_ex(file, **options)[0]
+            return "(%s %s; rm -f %s)&" % (command, quote(file), quote(file))
 
     # implementations