fix: export Picture

src/Data/Picture.hs

@@ -3,15 +3,16 @@
 {-# LANGUAGE TypeFamilies #-}
 
 {-|
-Module      : Picture
-Description : manipulation functions
+Module      : Data.Picture
+Description : picture manipulation functions
 Copyright   : (c) Mahdi Dibaiee, 2016
 License     : GPL-3
 Maintainer  : mdibaiee@aol.com
 Stability   : experimental
 Portability : POSIX
 -}
-module Data.Picture ( grayscale
+module Data.Picture ( Picture
+                    , grayscale
                     , readPicture
                     , fromImage
                     , toImage
@@ -31,7 +32,7 @@ module Data.Picture ( grayscale
     import System.IO
     import Data.Maybe
 
-    -- | 'Picture' type is just a triple of color channel matrices: (R, G, B)
+    -- | (R, G, B) color channels
     type Picture = (Matrix Double, Matrix Double, Matrix Double)
 
     -- | Converts a JuicyPixel 'Image PixelRGB8' to 'Picture'