diff --git a/py/htm/examples/mnist.py b/py/htm/examples/mnist.py
index d74ee0134d..25d1022e87 100644
--- a/py/htm/examples/mnist.py
+++ b/py/htm/examples/mnist.py
@@ -81,7 +81,7 @@ def load_images(file_name):
 default_parameters = {
     'potentialRadius': 7,
     'boostStrength': 7.0,
-    'columnDimensions': (28*28*8, 1),
+    'columnDimensions': (79, 79),
     'dutyCyclePeriod': 1402,
     'localAreaDensity': 0.1,
     'minPctOverlapDutyCycle': 0.2,