diff --git a/tensorflow/python/ops/image_ops_impl.py b/tensorflow/python/ops/image_ops_impl.py
index d9c0d637dc7..035ff7dcd2f 100644
--- a/tensorflow/python/ops/image_ops_impl.py
+++ b/tensorflow/python/ops/image_ops_impl.py
@@ -3757,7 +3757,10 @@ def rgb_to_yuv(images):
 
   Outputs a tensor of the same shape as the `images` tensor, containing the YUV
   value of the pixels.
-  The output is only well defined if the value in images are in [0,1].
+  The output is only well defined if the value in images are in [0, 1].
+  There are two ways of representing an image: [0, 255] pixel values range or 
+  [0, 1] (as float) pixel values range. Users need to convert the input image 
+  into a float [0, 1] range.
 
   Args:
     images: 2-D or higher rank. Image data to convert. Last dimension must be