diff --git a/Data/Conduit/ImageSize.hs b/Data/Conduit/ImageSize.hs
--- a/Data/Conduit/ImageSize.hs
+++ b/Data/Conduit/ImageSize.hs
@@ -7,7 +7,7 @@
     ) where
 
 import qualified Data.ByteString.Lazy as L
-import qualified Data.Conduit as C
+import Data.Conduit
 import qualified Data.Conduit.Binary as CB
 import qualified Data.ByteString as S
 import Data.ByteString.Char8 ()
@@ -22,28 +22,29 @@
 
 -- | Specialized version of 'sinkImageInfo' that returns only the
 -- image size.
-sinkImageSize :: Monad m => C.Sink S.ByteString m (Maybe Size)
+sinkImageSize :: Monad m => GLSink S.ByteString m (Maybe Size)
 sinkImageSize = fmap (fmap fst) sinkImageInfo
 
 -- | Find out the size of an image.  Also returns the file format
 -- that parsed correctly.  Note that this function does not
 -- verify that the file is indeed in the format that it returns,
 -- since it looks only at a small part of the header.
-sinkImageInfo :: Monad m => C.Sink S.ByteString m (Maybe (Size, FileFormat))
+sinkImageInfo :: Monad m => GLSink S.ByteString m (Maybe (Size, FileFormat))
 sinkImageInfo =
-    C.NeedInput (pushHeader id) close
+    start id
   where
-    close = return Nothing
+    start front = await >>= maybe (return Nothing) (pushHeader front)
+
     pushHeader front bs'
         | S.length bs >= 11 && S.take 5 (S.drop 6 bs) ==
             S.pack [0x4A, 0x46, 0x49, 0x46, 0x00] =
-                sinkPush jpg $ S.drop 4 bs
+                leftover (S.drop 4 bs) >> jpg
         | S.length bs >= 6 && S.take 6 bs `elem` gifs =
-            sinkPush gif $ S.drop 6 bs
+            leftover (S.drop 6 bs) >> gif
         | S.length bs >= 8 && S.take 8 bs == S.pack [137, 80, 78, 71, 13, 10, 26, 10] =
-            sinkPush png $ S.drop 8 bs
-        | S.length bs < 11 = C.NeedInput (pushHeader $ S.append bs) close
-        | otherwise = C.Done (Just bs) Nothing
+            leftover (S.drop 8 bs) >> png
+        | S.length bs < 11 = start $ S.append bs
+        | otherwise = leftover bs >> return Nothing
       where
         bs = front bs'
 
@@ -65,9 +66,6 @@
                 return $ (\w h -> (Size w h, PNG)) <$> mw <*> mh
             else return Nothing
 
-    sinkPush (C.NeedInput push _) x = push x
-    sinkPush _ _ = error "Data.Conduit.ImageSize.sinkPush"
-
     jpg = do
         mi <- getInt 2 0
         case mi of
@@ -94,7 +92,7 @@
 getInt :: (Monad m, Integral i)
        => Int
        -> i
-       -> C.Sink S.ByteString m (Maybe i)
+       -> Pipe S.ByteString S.ByteString o u m (Maybe i)
 getInt 0 i = return $ Just i
 getInt len i = do
     mx <- CB.head
diff --git a/imagesize-conduit.cabal b/imagesize-conduit.cabal
--- a/imagesize-conduit.cabal
+++ b/imagesize-conduit.cabal
@@ -1,5 +1,5 @@
 Name:                imagesize-conduit
-Version:             0.4.0
+Version:             0.5.0
 Synopsis:            Determine the size of some common image formats.
 Description:         Currently supports PNG, GIF, and JPEG. This package provides a Sink that will consume the minimum number of bytes necessary to determine the image dimensions.
 License:             BSD3
@@ -18,7 +18,7 @@
 Library
   Exposed-modules:     Data.Conduit.ImageSize
   Build-depends:       base                     >= 4            && < 5
-                     , conduit                  >= 0.4          && < 0.5
+                     , conduit                  >= 0.5          && < 0.6
                      , bytestring               >= 0.9
   ghc-options:     -Wall
 
diff --git a/test/main.hs b/test/main.hs
--- a/test/main.hs
+++ b/test/main.hs
@@ -8,7 +8,7 @@
 import Test.HUnit
 
 main :: IO ()
-main = hspecX $ do
+main = hspec $ do
     describe "image size" $ do
         it "png" $ check (Just $ Size 271 61) "test/logo.png"
         it "jpg" $ check (Just $ Size 271 61) "test/logo.jpg"