diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
index 0f874d46f277..d7607c368231 100644
--- a/lib/matplotlib/image.py
+++ b/lib/matplotlib/image.py
@@ -964,6 +964,12 @@ def set_array(self, *args):
         raise NotImplementedError('Method not supported')
 
     def set_interpolation(self, s):
+        """
+        Parameters
+        ----------
+        s : str, None
+            Either 'nearest', 'bilinear', or ``None``.
+        """
         if s is not None and s not in ('nearest', 'bilinear'):
             raise NotImplementedError('Only nearest neighbor and '
                                       'bilinear interpolations are supported')