diff --git a/scikits/image/io/tests/test_plugin_util.py b/scikits/image/io/tests/test_plugin_util.py
new file mode 100644
index 00000000..4d1e2473
--- /dev/null
+++ b/scikits/image/io/tests/test_plugin_util.py
@@ -0,0 +1,35 @@
+from scikits.image.io._plugins.util import prepare_for_display, WindowManager
+
+from numpy.testing import *
+import numpy as np
+
+class TestPrepareForDisplay:
+    def test_basic(self):
+        prepare_for_display(np.random.random((10, 10)))
+
+    def test_dtype(self):
+        x = prepare_for_display(np.random.random((10, 15)))
+        assert x.dtype == np.dtype(np.uint8)
+
+    def test_grey(self):
+        x = prepare_for_display(np.arange(12, dtype=float).reshape((4,3))/11.)
+        assert_array_equal(x[..., 0], x[..., 2])
+        assert x[0, 0, 0] == 0
+        assert x[3, 2, 0] == 255
+
+    def test_colour(self):
+        x = prepare_for_display(np.random.random((10, 10, 3)))
+
+    def test_alpha(self):
+        x = prepare_for_display(np.random.random((10, 10, 4)))
+
+    @raises(ValueError)
+    def test_wrong_dimensionality(self):
+        x = prepare_for_display(np.random.random((10, 10, 1, 1)))
+
+    @raises(ValueError)
+    def test_wrong_depth(self):
+        x = prepare_for_display(np.random.random((10, 10, 5)))
+
+if __name__ == "__main__":
+    run_module_suite()