Check that image is larger than template.

skimage/feature/template.py

@@ -33,6 +33,8 @@ def match_template(image, template, pad_output=True):
         beyond the image edges.
 
     """
+    if np.any(np.less(image.shape, template.shape)):
+        raise ValueError("Image must be larger than template.")
     image = _convert(image, np.float32)
     template = _convert(template, np.float32)
 

skimage/feature/tests/test_template.py

@@ -70,6 +70,12 @@ def test_normalization():
     assert np.allclose(result.flat[iflat_max], 1)
 
 
+def test_switched_arguments():
+    image = np.ones((5, 5))
+    template = np.ones((3, 3))
+    np.testing.assert_raises(ValueError, match_template, template, image)
+
+
 if __name__ == "__main__":
     from numpy import testing
     testing.run_module_suite()