diff --git a/JuicyPixels.cabal b/JuicyPixels.cabal
--- a/JuicyPixels.cabal
+++ b/JuicyPixels.cabal
@@ -1,5 +1,5 @@
 Name:                JuicyPixels
-Version:             3.1.5.1
+Version:             3.1.5.2
 Synopsis:            Picture loading/serialization (in png, jpeg, bitmap, gif, tiff and radiance)
 Description:
     <<data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAMAAAADABAMAAACg8nE0AAAAElBMVEUAAABJqDSTWEL/qyb///8AAABH/1GTAAAAAXRSTlMAQObYZgAAAN5JREFUeF7s1sEJgFAQxFBbsAV72v5bEVYWPwT/XDxmCsi7zvHXavYREBDI3XP2GgICqBBYuwIC+/rVayPUAyAg0HvIXBcQoDFDGnUBgWQQ2Bx3AYFaRoBpAQHWb3bt2ARgGAiCYFFuwf3X5HA/McgGJWI2FdykCv4aBYzmKwDwvl6NVmUAAK2vlwEALK7fo88GANB6HQsAAAAAAAAA7P94AQCzswEAAAAAAAAAAAAAAAAAAICzh4UAO4zWAYBfRutHA4Bn5C69JhowAMGoBaMWDG0wCkbBKBgFo2AUAACPmegUST/IJAAAAABJRU5ErkJggg==>>
@@ -27,7 +27,7 @@
 Source-Repository this
     Type:      git
     Location:  git://github.com/Twinside/Juicy.Pixels.git
-    Tag:       v3.1.5.1
+    Tag:       v3.1.5.2
 
 Flag Mmap
     Description: Enable the file loading via mmap (memory map)
@@ -51,10 +51,10 @@
   Ghc-prof-options: -rtsopts -Wall -prof -auto-all
   Build-depends: base                >= 4       && < 5,
                  bytestring          >= 0.9     && < 0.11,
-                 mtl                 >= 1.1     && < 2.2,
+                 mtl                 >= 1.1     && < 2.3,
                  binary              >= 0.5     && < 0.8,
                  zlib                >= 0.5.3.1 && < 0.6,
-                 transformers        >= 0.2.2   && < 0.4,
+                 transformers        >= 0.2.2   && < 0.5,
                  vector              >= 0.9     && < 0.11,
                  primitive           >= 0.5     && < 0.6,
                  deepseq             >= 1.1     && < 1.4,
diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,5 +1,8 @@
 -*-change-log-*-
 
+v3.1.5.2 May 2014
+ * Bumping the transformers dependency
+
 v3.1.5.1 May 2014
  * Adding some INLINE annotations for some pixel functions
 
diff --git a/src/Codec/Picture/BitWriter.hs b/src/Codec/Picture/BitWriter.hs
--- a/src/Codec/Picture/BitWriter.hs
+++ b/src/Codec/Picture/BitWriter.hs
@@ -30,7 +30,7 @@
 import Control.Monad.ST( ST )
 import qualified Control.Monad.Trans.State.Strict as S
 import Data.Word( Word8, Word32 )
-import Data.Bits( Bits, (.&.), (.|.), unsafeShiftR, unsafeShiftL )
+import Data.Bits( (.&.), (.|.), unsafeShiftR, unsafeShiftL )
 
 import Codec.Picture.VectorByteConversion( blitVector )
 import qualified Data.Vector.Storable.Mutable as M
diff --git a/src/Codec/Picture/ColorQuant.hs b/src/Codec/Picture/ColorQuant.hs
--- a/src/Codec/Picture/ColorQuant.hs
+++ b/src/Codec/Picture/ColorQuant.hs
@@ -114,7 +114,7 @@
     (bg, br, bb) = bitDiv3 maxCols
     (dr, dg, db) = (2^(8-br), 2^(8-bg), 2^(8-bb))
     paletteIndex (PixelRGB8 r g b) = fromIntegral $ fromMaybe 0 (elemIndex
-      (PixelRGB8 (r .&. (256 - dr)) (g .&. (256 - dg)) (b .&. (256 - db)))
+      (PixelRGB8 (r .&. (255 - dr)) (g .&. (255 - dg)) (b .&. (255 - db)))
       paletteList)
 
 isColorCountBelow :: Int -> Image PixelRGB8 -> (Set.Set PixelRGB8, Bool)
diff --git a/src/Codec/Picture/Jpg/FastDct.hs b/src/Codec/Picture/Jpg/FastDct.hs
--- a/src/Codec/Picture/Jpg/FastDct.hs
+++ b/src/Codec/Picture/Jpg/FastDct.hs
@@ -2,7 +2,7 @@
 
 import Control.Applicative( (<$>) )
 import Data.Int( Int16, Int32 )
-import Data.Bits( Bits, unsafeShiftR, unsafeShiftL )
+import Data.Bits( unsafeShiftR, unsafeShiftL )
 import Control.Monad.ST( ST )
 
 import qualified Data.Vector.Storable.Mutable as M