diff --git a/tests/python_tests/images/support/mapnik-marker-ellipse-render1.png b/tests/python_tests/images/support/mapnik-marker-ellipse-render1.png
index 4ef3f550c..b6563ebd1 100644
Binary files a/tests/python_tests/images/support/mapnik-marker-ellipse-render1.png and b/tests/python_tests/images/support/mapnik-marker-ellipse-render1.png differ
diff --git a/tests/python_tests/images/support/mapnik-marker-ellipse-render2.png b/tests/python_tests/images/support/mapnik-marker-ellipse-render2.png
index 8201f95b8..4479d5c0d 100644
Binary files a/tests/python_tests/images/support/mapnik-marker-ellipse-render2.png and b/tests/python_tests/images/support/mapnik-marker-ellipse-render2.png differ
diff --git a/tests/python_tests/markers_complex_rendering_test.py b/tests/python_tests/markers_complex_rendering_test.py
index 756b65073..09c5baf85 100644
--- a/tests/python_tests/markers_complex_rendering_test.py
+++ b/tests/python_tests/markers_complex_rendering_test.py
@@ -18,7 +18,7 @@ if 'csv' in mapnik.DatasourceCache.plugin_names():
         mapnik.render(m,im)
         actual = '/tmp/mapnik-marker-ellipse-render1.png'
         expected = 'images/support/mapnik-marker-ellipse-render1.png'
-        im.save(actual)
+        im.save(actual,'png32')
         expected_im = mapnik.Image.open(expected)
         eq_(im.tostring('png32'),expected_im.tostring('png32'), 'failed comparing actual (%s) and expected (%s)' % (actual,'tests/python_tests/'+ expected))
 
@@ -31,7 +31,7 @@ if 'csv' in mapnik.DatasourceCache.plugin_names():
         mapnik.render(m,im)
         actual = '/tmp/mapnik-marker-ellipse-render2.png'
         expected = 'images/support/mapnik-marker-ellipse-render2.png'
-        im.save(actual)
+        im.save(actual,'png32')
         expected_im = mapnik.Image.open(expected)
         eq_(im.tostring('png32'),expected_im.tostring('png32'), 'failed comparing actual (%s) and expected (%s)' % (actual,'tests/python_tests/'+ expected))