diff --git a/baselines/common/models.py b/baselines/common/models.py
index 0763095..8088e7d 100644
--- a/baselines/common/models.py
+++ b/baselines/common/models.py
@@ -138,7 +138,7 @@ def conv_only(convs=[(32, 8, 4), (64, 4, 2), (64, 3, 1)], **conv_kwargs):
     '''
 
     def network_fn(X):
-        out = X
+        X = tf.cast(X, tf.float32) / 255.
         with tf.variable_scope("convnet"):
             for num_outputs, kernel_size, stride in convs:
                 out = layers.convolution2d(out,