diff --git a/h-booru.cabal b/h-booru.cabal
--- a/h-booru.cabal
+++ b/h-booru.cabal
@@ -1,5 +1,5 @@
 name:                h-booru
-version:             0.2.0.0
+version:             0.3.0.0
 synopsis:            Haskell library for retrieving data from various booru image sites
 description:         Haskell library for retrieving data from various booru image sites.
                      By providing a common interface for such sites and some parsers for
@@ -13,40 +13,66 @@
 category:            Web
 build-type:          Simple
 extra-source-files:  README.md
-cabal-version:       >=1.10
+cabal-version:       >=1.16
+
 source-repository head
   type:     git
   location: git@github.com:Fuuzetsu/h-booru.git
 
 library
+  ghc-options:         -O2 -threaded
   hs-source-dirs:      src
   default-language:    Haskell2010
   exposed-modules:
     HBooru.Types
     HBooru.Network
+    HBooru.Parsers.FieldParsers
     HBooru.Parsers.Gelbooru
     HBooru.Parsers.Ichijou
     HBooru.Parsers.Konachan
     HBooru.Parsers.Safebooru
     HBooru.Parsers.Yandere
-  build-depends:       base >=4.6 && <5, hxt >= 9.3.1.2, template-haskell
-                       , http-conduit, utf8-string, bytestring, vinyl >= 0.4
-
+  build-depends:
+      base >=4 && <5
+    , bytestring
+    , filepath
+    , http-conduit
+    , hxt >= 9.3.1.2
+    , mtl
+    , stm
+    , template-haskell
+    , transformers
+    , utf8-string
+    , vinyl >= 0.4
 
 executable h-booru
+  ghc-options:         -O2 -threaded
   hs-source-dirs:      src
   default-language:    Haskell2010
   main-is: Main.hs
   other-modules:
     HBooru.Types
     HBooru.Network
+    HBooru.Parsers.FieldParsers
     HBooru.Parsers.Gelbooru
     HBooru.Parsers.Ichijou
     HBooru.Parsers.Konachan
     HBooru.Parsers.Safebooru
     HBooru.Parsers.Yandere
-  build-depends:       base >=4.6 && <5, hxt >= 9.3.1.2, template-haskell
-                       , http-conduit, utf8-string, bytestring, vinyl >= 0.4
+  build-depends:
+      base >=4 && <5
+    , bytestring
+    , containers
+    , directory
+    , filepath
+    , http-conduit
+    , hxt >= 9.3.1.2
+    , mtl
+    , stm
+    , template-haskell
+    , transformers
+    , utf8-string
+    , vinyl >= 0.4
 
 source-repository head
   type:     git
diff --git a/src/HBooru/Network.hs b/src/HBooru/Network.hs
--- a/src/HBooru/Network.hs
+++ b/src/HBooru/Network.hs
@@ -1,4 +1,8 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
+
 -- |
 -- Module      :  HBooru.Network
 -- Copyright   :  (c) Mateusz Kowalczyk 2013-2014
@@ -14,10 +18,18 @@
 module HBooru.Network where
 
 import Control.Applicative ((<$>))
-import HBooru.Types
-import Network.HTTP.Conduit (simpleHttp)
-import Data.ByteString.Lazy (toStrict)
+import Control.Concurrent
+import Control.Concurrent.STM
+import Control.Exception
+import Control.Monad
+import Control.Monad.IO.Class
+import Control.Monad.Trans.Error
+import Data.ByteString.Lazy (toStrict, writeFile)
 import Data.ByteString.UTF8
+import Data.Either (rights)
+import HBooru.Parsers.Ichijou
+import HBooru.Types
+import Network.HTTP.Conduit (simpleHttp, HttpException(..))
 
 -- | Given a 'Site', 'DataFormat' and a list of 'Tag's, naively fetch the first
 -- page or so and parse it to the appropriate image type. Both the site and the
@@ -25,34 +37,38 @@
 -- has to exist in an instance of 'CoerceResponse'. Uses 'fetchPostPage' to
 -- fetch the data.
 fetchTaggedPosts
-  ∷ (Postable s d, CoerceResponse d r) ⇒ s → d → [Tag] → IO [ImageTy s d]
+  ∷ (Postable s d, CoerceResponse d r) ⇒ s → d → [Tag] → ExcIO [ImageTy s d]
 fetchTaggedPosts s d ts = parseResponse s <$> fetchPostPage s d ts
 
 -- | As 'fetchTaggedPosts' but works with sites which allow indexing by page.
 fetchTaggedPostsIndexed ∷ (CoerceResponse r a, PostablePaged s r)
-                          ⇒ s → r → [Tag] → Integer → IO [ImageTy s r]
+                          ⇒ s → r → [Tag] → Integer → ExcIO [ImageTy s r]
 fetchTaggedPostsIndexed s d ts i =
   parseResponse s <$> fetchPostPageIndexed s d ts i
 
 -- | Given an instance of 'Postable', 'CoerceResponse', and a list of 'Tag's,
 -- fetch the post page.
-fetchPostPage ∷ (Postable s d, CoerceResponse d r) ⇒ s → d → [Tag] → IO r
+fetchPostPage ∷ (Postable s d, CoerceResponse d r) ⇒ s → d → [Tag] → ExcIO r
 fetchPostPage s d ts = fetchResponse (postUrl s d ts) d
 
 -- | Given an instance of 'Postable', 'CoerceResponse', and a list of 'Tag's,
 -- fetch the post page.
 fetchPostPageIndexed ∷ (PostablePaged s d, CoerceResponse d r)
-                       ⇒ s → d → [Tag] → Integer → IO r
+                       ⇒ s → d → [Tag] → Integer → ExcIO r
 fetchPostPageIndexed s d ts i = fetchResponse (postUrlPaged s d ts i) d
 
 -- | Given a URL and protocol, tries to fetch a response.
-fetchResponse ∷ CoerceResponse r r' ⇒ String → r → IO r'
-fetchResponse u r = toResponse r . toString . toStrict <$> simpleHttp u
+fetchResponse ∷ CoerceResponse r r' ⇒ String → r → ExcIO r'
+fetchResponse u r = do
+  liftIO (try (simpleHttp u)) >>= \case
+    Left (e ∷ HttpException) → throwError $ Network e
+    Right x → return . toResponse r . toString . toStrict $ x
 
 -- | Uses 'fetchPostPage' to parse the number of posts available based on
 -- provided 'Tag's.
 fetchPostCount
-  ∷ (Postable s r, Counted s r, CoerceResponse r a) ⇒ s → r → [Tag] → IO Integer
+  ∷ (Postable s r, Counted s r, CoerceResponse r a) ⇒ s → r → [Tag]
+  → ExcIO Integer
 fetchPostCount s d ts = parseCount s <$> fetchPostPage s d ts
 
 -- | Attemps to fetch all posts from a site, from all its pages. The
@@ -60,8 +76,48 @@
 fetchAllTaggedPosts
   ∷ (CoerceResponse r a, PostablePaged s r) ⇒ s → r → [Tag] → IO [ImageTy s r]
 fetchAllTaggedPosts s r ts = do
-  count ← fromIntegral <$> fetchPostCount s r ts
-  let pages = case hardLimit s r of
-        NoLimit → 0
-        Limit x → max 0 (ceiling $ (count / fromIntegral x) - 1)
-  concat <$> mapM (fetchTaggedPostsIndexed s r ts) [0 .. pages]
+  runErrorT (fetchPostCount s r ts) >>= \case
+    Left e → print e >> return []
+    Right i → do
+      let count = fromIntegral i ∷ Double
+          pages = case hardLimit s r of
+            NoLimit → 0
+            Limit x → max 0 (ceiling $ (count / fromIntegral x) - 1)
+      r' ← mapM (runErrorT . fetchTaggedPostsIndexed s r ts) [0 .. pages]
+      return . concat $ rights r'
+
+data DownloadStatus = OK String
+                    | Failed (Either HttpException IOException, String)
+                    | EndOfQueue
+                    deriving Show
+
+-- | Downloads the given files. Writes the status information back to
+-- the provided TChan.
+downloadFiles ∷ [(String, FilePath)] -- ^ URL with save location
+              → TChan DownloadStatus -- ^ Channel to send back status info on
+              → Int -- ^ Max threads to run at once. Bounded to minimum of 1.
+              → IO ()
+downloadFiles ts ds mt = do
+  tv ← atomically $ newTVar ts
+  count ← atomically $ newTVar (0 ∷ Int)
+  let maxThreads = max 1 mt
+      wf x = x `seq` Data.ByteString.Lazy.writeFile x
+      modCount f = atomically $ modifyTVar count (\x -> max 0 (f x))
+      runDownload (url, path) =
+        try (simpleHttp url) >>= \case
+          Left (e ∷ HttpException) →
+            atomically . writeTChan ds $ Failed (Left e, url)
+          Right c → try (wf path c) >>= atomically . \case
+            Left (e ∷ IOException) → writeTChan ds $ Failed (Right e, url)
+            Right _ → writeTChan ds $ OK url
+      readVs = atomically $ liftM2 (,) (readTVar tv) (readTVar count)
+      spawnThreads = readVs >>= \case
+        ([], 0) → atomically $ writeTChan ds EndOfQueue
+        (ys, n) | n >= maxThreads → spawnThreads
+                | otherwise → case ys of
+                  [] → threadDelay 10000 >> spawnThreads
+                  x:xs → void $ do
+                    atomically (writeTVar tv xs)
+                    forkIO $ modCount succ >> runDownload x >> modCount pred
+                    spawnThreads
+  spawnThreads
diff --git a/src/HBooru/Parsers/FieldParsers.hs b/src/HBooru/Parsers/FieldParsers.hs
new file mode 100644
--- /dev/null
+++ b/src/HBooru/Parsers/FieldParsers.hs
@@ -0,0 +1,263 @@
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
+
+-- |
+-- Module      :  HBooru.Parsers.FieldParsers
+-- Copyright   :  (c) Mateusz Kowalczyk 2014
+-- License     :  GPL-3
+--
+-- Maintainer  :  fuuzetsu@fuuzetsu.co.uk
+-- Stability   :  experimental
+--
+-- A collection of arrow parsers for known fields. We can use these
+-- (and write new ones) by composing these parsers together for each site we
+-- want to parse. As we carry the field information with us, this can later be
+-- used when trying to extract the parsed information from the sites into a
+-- homogenous list. Currently this moduel only deals with parsing out XML
+-- attributes.
+module HBooru.Parsers.FieldParsers where
+
+import Control.Applicative
+import Control.Exception.Base (Exception)
+import Control.Monad
+import Control.Monad.Error
+import Data.Maybe
+import Data.Monoid
+import Data.Typeable
+import Data.Vinyl
+import HBooru.Types
+import Prelude
+import Text.Read (readMaybe)
+import Text.XML.HXT.Core hiding (mkName, (<+>))
+
+import Data.Vinyl.TyFun
+
+newtype E = E String deriving (Show, Eq, Typeable)
+instance Exception E where
+
+-- | Alias for the common constraint blob
+type ParseArrow cat = (Functor (cat XmlTree), ArrowXml cat)
+
+-- | Alias for named fields
+type Field cat s = cat XmlTree (Parse (R '[s]))
+
+-- | Helper that provides better error messages when a 'read' fails.
+readAttr ∷ (ArrowXml cat, Read (App ElF s), Functor (cat XmlTree)) ⇒ String
+         → sing s → Field cat s
+readAttr s f = readAttrWith s f readMaybe
+
+readAttrWith ∷ (ArrowXml cat, Functor (cat XmlTree)) ⇒ String → sing s
+             → (String → Maybe (App ElF s)) → Field cat s
+readAttrWith s f r = readCustom s f (\x → handler x $ r x)
+  where
+    handler inp Nothing = throwError . PF $ mconcat [s, ": '", inp, "'"]
+    handler _ (Just x) = return x
+
+readCustom ∷ (ArrowXml cat, Functor (cat XmlTree)) ⇒ String
+           → sing s → (String → Parse (App ElF s)) → Field cat s
+readCustom s f h = fmap (f =:) . h <$> getAttrValue s
+
+readNormalAttr ∷ (ArrowXml cat, (App ElF s) ~ String, Functor (cat XmlTree))
+               ⇒ String → sing s → Field cat s
+readNormalAttr s f = return . (f =:) <$> getAttrValue s
+
+-- * Individual attribute parsers
+
+-- | Parser arrow for a "height" XML attribute.
+heightA ∷ ParseArrow cat ⇒ Field cat "height"
+heightA = readAttr "height" height
+
+-- | Parser arrow for a "score" XML attribute.
+scoreA ∷ ParseArrow cat ⇒ Field cat "score"
+scoreA = readAttr "score" score
+
+-- | Parser arrow for a "file_url" XML attribute.
+file_urlA ∷ ParseArrow cat ⇒ Field cat "file_url"
+file_urlA = readNormalAttr "file_url" file_url
+
+-- | Parser arrow for a "parent_id" XML attribute.
+parent_idA ∷ ParseArrow cat ⇒ Field cat "parent_id"
+parent_idA = readCustom "parent_id" parent_id handler
+  where
+    handler = return . readMaybe
+
+-- | Parser arrow for a "sample_url" XML attribute.
+sample_urlA ∷ ParseArrow cat ⇒ Field cat "sample_url"
+sample_urlA = readNormalAttr "sample_url" sample_url
+
+-- | Parser arrow for a "sample_width" XML attribute.
+sample_widthA ∷ ParseArrow cat ⇒ Field cat "sample_width"
+sample_widthA = readAttr "sample_width" sample_width
+
+-- | Parser arrow for a "sample_height" XML attribute.
+sample_heightA ∷ ParseArrow cat ⇒ Field cat "sample_height"
+sample_heightA = readAttr "sample_height" sample_height
+
+-- | Parser arrow for a "preview_url" XML attribute.
+preview_urlA ∷ ParseArrow cat ⇒ Field cat "preview_url"
+preview_urlA = readNormalAttr "preview_url" preview_url
+
+-- | Parser arrow for a "rating" XML attribute.
+ratingA ∷ ParseArrow cat ⇒ Field cat "rating"
+ratingA = readAttrWith "rating" rating parseRating
+
+-- | Parser arrow for a "tags" XML attribute.
+tagsA ∷ ParseArrow cat ⇒ Field cat "tags"
+tagsA = readCustom "tags" tags (return . parseTags)
+
+-- | Parser arrow for a "id" XML attribute.
+idA ∷ ParseArrow cat ⇒ Field cat "id"
+idA = readAttr "id" HBooru.Types.id
+
+-- | Parser arrow for a "width" XML attribute.
+widthA ∷ ParseArrow cat ⇒ Field cat "width"
+widthA = readAttr "width" width
+
+-- | Parser arrow for a "change" XML attribute.
+changeA ∷ ParseArrow cat ⇒ Field cat "change"
+changeA = readAttr "change" change
+
+-- | Parser arrow for a "md5" XML attribute.
+md5A ∷ ParseArrow cat ⇒ Field cat "md5"
+md5A = readNormalAttr "md5" md5
+
+-- | Parser arrow for a "creator_id" XML attribute.
+creator_idA ∷ ParseArrow cat ⇒ Field cat "creator_id"
+creator_idA = readAttr "creator_id" creator_id
+
+-- | Parser arrow for a "has_children" XML attribute.
+has_childrenA ∷ ParseArrow cat ⇒ Field cat "has_children"
+has_childrenA = readAttrWith "has_children" has_children parseBool
+
+-- | Parser arrow for a "created_at" XML attribute.
+created_atA ∷ ParseArrow cat ⇒ Field cat "created_at"
+created_atA = readNormalAttr "created_at" created_at
+
+-- | Parser arrow for a "status" XML attribute.
+statusA ∷ ParseArrow cat ⇒ Field cat "status"
+statusA = readNormalAttr "status" status
+
+-- | Parser arrow for a "source" XML attribute.
+sourceA ∷ ParseArrow cat ⇒ Field cat "source"
+sourceA = readNormalAttr "source" source
+
+-- | Parser arrow for a "has_notes" XML attribute.
+has_notesA ∷ ParseArrow cat ⇒ Field cat "has_notes"
+has_notesA = readAttrWith "has_notes" has_notes (return . parseBool)
+
+-- | Parser arrow for a "has_comments" XML attribute.
+has_commentsA ∷ ParseArrow cat ⇒ Field cat "has_comments"
+has_commentsA = readAttrWith "has_comments" has_comments (return . parseBool)
+
+-- | Parser arrow for a "preview_width" XML attribute.
+preview_widthA ∷ ParseArrow cat ⇒ Field cat "preview_width"
+preview_widthA = readAttr "preview_width" preview_width
+
+-- | Parser arrow for a "preview_height" XML attribute.
+preview_heightA ∷ ParseArrow cat ⇒ Field cat "preview_height"
+preview_heightA = readAttr "preview_height" preview_height
+
+-- | Parser arrow for a "author" XML attribute.
+authorA ∷ ParseArrow cat ⇒ Field cat "author"
+authorA = readNormalAttr "author" author
+
+-- | Parser arrow for a "actual_preview_height" XML attribute.
+actual_preview_heightA ∷ ParseArrow cat ⇒ Field cat "actual_preview_height"
+actual_preview_heightA = readAttr "actual_preview_height" actual_preview_height
+
+-- | Parser arrow for a "actual_preview_width" XML attribute.
+actual_preview_widthA ∷ ParseArrow cat ⇒ Field cat "actual_preview_width"
+actual_preview_widthA = readAttr "actual_preview_width" actual_preview_width
+
+-- | Parser arrow for a "frames" XML attribute.
+framesA ∷ ParseArrow cat ⇒ Field cat "frames"
+framesA = readNormalAttr "frames" frames
+
+-- | Parser arrow for a "frames_pending" XML attribute.
+frames_pendingA ∷ ParseArrow cat ⇒ Field cat "frames_pending"
+frames_pendingA = readNormalAttr "frames_pending" frames_pending
+
+-- | Parser arrow for a "frames_pending_string" XML attribute.
+frames_pending_stringA ∷ ParseArrow cat ⇒ Field cat "frames_pending_string"
+frames_pending_stringA =
+  readNormalAttr "frames_pending_string" frames_pending_string
+
+-- | Parser arrow for a "frames_string" XML attribute.
+frames_stringA ∷ ParseArrow cat ⇒ Field cat "frames_string"
+frames_stringA = readNormalAttr "frames_string" frames_string
+
+-- | Parser arrow for a "is_held" XML attribute.
+is_heldA ∷ ParseArrow cat ⇒ Field cat "is_held"
+is_heldA = readAttrWith "is_held" is_held parseBool
+
+-- | Parser arrow for a "is_shown_in_index" XML attribute.
+is_shown_in_indexA ∷ ParseArrow cat ⇒ Field cat "is_shown_in_index"
+is_shown_in_indexA =
+  readAttrWith "is_shown_in_index" is_shown_in_index parseBool
+
+-- | Parser arrow for a "jpeg_file_size" XML attribute.
+jpeg_file_sizeA ∷ ParseArrow cat ⇒ Field cat "jpeg_file_size"
+jpeg_file_sizeA = readAttr "jpeg_file_size" jpeg_file_size
+
+-- | Parser arrow for a "jpeg_height" XML attribute.
+jpeg_heightA ∷ ParseArrow cat ⇒ Field cat "jpeg_height"
+jpeg_heightA = readAttr "jpeg_height" jpeg_height
+
+-- | Parser arrow for a "jpeg_url" XML attribute.
+jpeg_urlA ∷ ParseArrow cat ⇒ Field cat "jpeg_url"
+jpeg_urlA = readNormalAttr "jpeg_url" jpeg_url
+
+-- | Parser arrow for a "jpeg_width" XML attribute.
+jpeg_widthA ∷ ParseArrow cat ⇒ Field cat "jpeg_width"
+jpeg_widthA = readAttr "jpeg_width" jpeg_width
+
+-- | Parser arrow for a "sample_file_size" XML attribute.
+sample_file_sizeA ∷ ParseArrow cat ⇒ Field cat "sample_file_size"
+sample_file_sizeA = readAttr "sample_file_size" sample_file_size
+
+-- | Parser arrow for a "file_size" XML attribute.
+file_sizeA ∷ ParseArrow cat ⇒ Field cat "file_size"
+file_sizeA = readAttr "file_size" file_size
+
+-- * Parsing helpers
+
+-- | Parses a string returned from a Gelbooru-like site into
+-- one of the commonly used 'Rating's. Note that this is a partial function
+-- so you should make sure that the site in question only ever returns the
+-- values in a format specified in the function
+parseRating ∷ String → Maybe Rating
+parseRating "e" = Just Explicit
+parseRating "s" = Just HBooru.Types.Safe
+parseRating "q" = Just Questionable
+parseRating _ = Nothing
+
+-- | Splits returned tag string into separate 'Tag's. For Gelbooru-like
+-- sites, this is just the question of splitting on whitespace.
+parseTags ∷ String → [Tag]
+parseTags = words
+
+-- | Reads a lowercase 'Bool' string representation into its Haskell type. If we
+-- can't parse the boolean, return 'Nothing'.
+parseBool ∷ String → Maybe Bool
+parseBool "false" = Just False
+parseBool "true" = Just True
+parseBool _ = Nothing
+
+infixr 5 <:+>
+-- | A little helper that lifts '<+>' into 'Arrow' which allows us to
+-- compose parsers returning records very easily.
+(<:+>) ∷ Arrow cat ⇒ cat b (Parse (R as))
+       → cat b (Parse (R bs))
+       → cat b (Parse (R (as ++ bs)))
+x <:+> y = arr (uncurry pnd) <<< x &&& y
+  where
+    pnd ∷ Parse (R a) → Parse (R b) → Parse (R (a ++ b))
+    pnd (Left x') _ = Left x'
+    pnd _ (Left y') = Left y'
+    pnd (Right x') (Right y') = Right (x' <+> y')
diff --git a/src/HBooru/Parsers/Gelbooru.hs b/src/HBooru/Parsers/Gelbooru.hs
--- a/src/HBooru/Parsers/Gelbooru.hs
+++ b/src/HBooru/Parsers/Gelbooru.hs
@@ -1,8 +1,8 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Parsers.Gelbooru
@@ -16,13 +16,12 @@
 module HBooru.Parsers.Gelbooru where
 
 import Data.List
-import Data.Vinyl
 import HBooru.Parsers.FieldParsers
 import HBooru.Types
 import Text.XML.HXT.Core hiding (mkName)
 
 -- | Record used for Gelbooru posts
-type GelbooruPost = R
+type GelbooruPost = PR
   '[ "height"
    , "score"
    , "file_url"
@@ -59,7 +58,7 @@
 
 -- | We use this type and its 'Site' instance to distinguish
 -- between various parsers.
-data Gelbooru = Gelbooru
+data Gelbooru = Gelbooru deriving (Show, Eq)
 
 instance Postable Gelbooru XML where
   postUrl _ _ ts =
diff --git a/src/HBooru/Parsers/Ichijou.hs b/src/HBooru/Parsers/Ichijou.hs
--- a/src/HBooru/Parsers/Ichijou.hs
+++ b/src/HBooru/Parsers/Ichijou.hs
@@ -1,8 +1,8 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Parsers.Ichijou
@@ -16,17 +16,16 @@
 module HBooru.Parsers.Ichijou where
 
 import Data.List
-import Data.Vinyl
 import HBooru.Parsers.FieldParsers
 import HBooru.Types
 import Text.XML.HXT.Core hiding (mkName)
 
 -- | We use this type and its 'Site' instance to distinguish
 -- between various parsers.
-data Ichijou = Ichijou
+data Ichijou = Ichijou deriving (Show, Eq)
 
 -- | Ichijou post record alias
-type IchijouPost = R
+type IchijouPost = PR
   '[ "creator_id"
    , "md5"
    , "status"
diff --git a/src/HBooru/Parsers/Konachan.hs b/src/HBooru/Parsers/Konachan.hs
--- a/src/HBooru/Parsers/Konachan.hs
+++ b/src/HBooru/Parsers/Konachan.hs
@@ -1,8 +1,8 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Parsers.Konachan
@@ -17,17 +17,16 @@
 module HBooru.Parsers.Konachan where
 
 import Data.List
-import Data.Vinyl
 import HBooru.Parsers.FieldParsers
 import HBooru.Types
 import Text.XML.HXT.Core hiding (mkName)
 
 -- | We use this type and its 'Site' instance to distinguish
 -- between various parsers.
-data Konachan = Konachan
+data Konachan = Konachan deriving (Show, Eq)
 
 -- | Konachan post record
-type KonachanPost = R
+type KonachanPost = PR
   '[ "actual_preview_height"
    , "actual_preview_width"
    , "author"
diff --git a/src/HBooru/Parsers/Safebooru.hs b/src/HBooru/Parsers/Safebooru.hs
--- a/src/HBooru/Parsers/Safebooru.hs
+++ b/src/HBooru/Parsers/Safebooru.hs
@@ -1,8 +1,8 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Parsers.Safebooru
@@ -16,17 +16,16 @@
 module HBooru.Parsers.Safebooru where
 
 import Data.List
-import Data.Vinyl
 import HBooru.Parsers.FieldParsers
 import HBooru.Types
 import Text.XML.HXT.Core hiding (mkName)
 
 -- | We use this type and its 'Site' instance to distinguish
 -- between various parsers.
-data Safebooru = Safebooru
+data Safebooru = Safebooru deriving (Show, Eq)
 
 -- | Safebooru post record.
-type SafebooruPost = R
+type SafebooruPost = PR
   '[ "height"
    , "score"
    , "file_url"
diff --git a/src/HBooru/Parsers/Yandere.hs b/src/HBooru/Parsers/Yandere.hs
--- a/src/HBooru/Parsers/Yandere.hs
+++ b/src/HBooru/Parsers/Yandere.hs
@@ -1,8 +1,8 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Parsers.Yandere
@@ -13,21 +13,20 @@
 -- Stability   :  experimental
 --
 -- Module for parsing content from <http://yande.re/ Yandere>,
--- known in the past as <http://mou.imouto.org MouImouto>.
+-- known in the past as <http://moe.imouto.org MoeImouto>.
 module HBooru.Parsers.Yandere where
 
 import Data.List
-import Data.Vinyl
 import HBooru.Parsers.FieldParsers
 import HBooru.Types
 import Text.XML.HXT.Core hiding (mkName)
 
 -- | We use this type and its 'Site' instance to distinguish
 -- between various parsers.
-data Yandere = Yandere
+data Yandere = Yandere deriving (Show, Eq)
 
 -- | Alias for a record representing typical Yandere post.
-type YanderePost = R
+type YanderePost = PR
   '[ "actual_preview_height"
    , "actual_preview_width"
    , "author"
diff --git a/src/HBooru/Types.hs b/src/HBooru/Types.hs
--- a/src/HBooru/Types.hs
+++ b/src/HBooru/Types.hs
@@ -1,11 +1,11 @@
-{-# LANGUAGE UnicodeSyntax #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UnicodeSyntax #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# OPTIONS_HADDOCK show-extensions #-}
 
 -- |
 -- Module      :  HBooru.Types
@@ -18,11 +18,17 @@
 -- Module definining types used by the library.
 module HBooru.Types where
 
+import Control.Arrow
+import Control.Applicative
+import Control.Monad
+import Control.Exception
+import Control.Monad.Error
 import Data.Proxy
 import GHC.TypeLits (Symbol)
 import Data.Vinyl
 import Data.Vinyl.TH
-import Prelude hiding (id)
+import Network.HTTP.Conduit (HttpException(..))
+import Prelude
 import Text.XML.HXT.Core hiding (mkName, (<+>))
 
 -- | Tags used for searching in sites. No special escaping is done.
@@ -168,10 +174,41 @@
 instance Response JSONResponse where
   getResponse (JSONResponse x) = x
 
-
 instance Functor (LA XmlTree) where
   fmap f (LA g) = LA $ fmap fmap fmap f g
 
+bA ∷ ArrowApply cat ⇒ cat c' b → (b → cat c' c) → cat c' c
+bA mx f = (arr (\a -> mx >>> arr (\x -> (f x, a)) >>> app) &&& arr id) >>> app
+
+instance Applicative (LA XmlTree) where
+  pure x = LA . const $ return x
+  (<*>) = ap
+
+instance Monad (LA XmlTree) where
+  return = pure
+  (>>=) = bA
+
+-- | Parse failures from various parsers
+newtype ParseFailure = PF String deriving (Show, Eq)
+
+instance Error ParseFailure where
+  noMsg = PF noMsg
+  strMsg = PF . strMsg
+
+-- | Alias for our parser monad with failure possibility
+type Parse = Either ParseFailure
+
+data RealWorldExcs = Network HttpException
+                   | IOE IOException
+                   | SomethingElse String
+                   deriving (Show)
+
+instance Error RealWorldExcs where
+  noMsg = SomethingElse noMsg
+  strMsg = SomethingElse . strMsg
+
+type ExcIO a = ErrorT RealWorldExcs IO a
+
 makeUniverse' ''Symbol "ElF"
 semantics ''ElF [ [t| "height" |]                :~> [t| Integer |]
                 , [t| "score" |]                 :~> [t| Integer |]
@@ -184,8 +221,8 @@
                 , [t| "rating" |]                :~> [t| Rating |]
                 , [t| "tags" |]                  :~> [t| [Tag] |]
                 , [t| "id" |]                    :~> [t| Integer |]
-                , [t| "width" |]                 :~> [t| String |]
-                , [t| "change" |]                :~> [t| String |]
+                , [t| "width" |]                 :~> [t| Integer |]
+                , [t| "change" |]                :~> [t| Int |]
                 , [t| "md5" |]                   :~> [t| String |]
                 , [t| "creator_id" |]            :~> [t| Integer |]
                 , [t| "has_children" |]          :~> [t| Bool |]
@@ -215,6 +252,9 @@
 
 -- | Handy synonym hiding 'ElF'.
 type R a = PlainRec ElF a
+
+-- | 'R' wrapped in a 'Parse'.
+type PR a = Parse (R a)
 
 -- * Commonly used fields
 
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,9 +1,16 @@
 {-# LANGUAGE UnicodeSyntax #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE DataKinds #-}
 module Main where
 
 import Control.Applicative ((<$>))
-import Data.Vinyl
+import Control.Concurrent (forkIO)
+import Control.Concurrent.STM
+import Control.Monad (void, filterM)
+import Data.Map
+import Data.Monoid
+import Data.Vinyl (rGet)
 import HBooru.Network
 import HBooru.Parsers.Gelbooru
 import HBooru.Parsers.Ichijou
@@ -11,27 +18,76 @@
 import HBooru.Parsers.Safebooru
 import HBooru.Parsers.Yandere
 import HBooru.Types
+import System.Directory
 import System.Environment (getArgs)
+import System.Exit
+import System.FilePath
 
 main ∷ IO ()
 main = getArgs >>= \case
-  [] → putStrLn help
-  xs → fetchImageLinks xs >>= mapM_ putStrLn
+  [] → putStr help
+  "-d":d:ts → downloadTo d ts
+  xs → fetchImageLinks xs >>= \x → mapM_ putStrLn [ y | Right y ← x ]
 
-fetchImageLinks ∷ [Tag] → IO [String]
+-- | Downloads all the images with the given tag to the given
+-- directory.
+downloadTo ∷ FilePath → [Tag] → IO ()
+downloadTo fp xs = doesDirectoryExist fp >>= \case
+  False → print (fp <> " doesn't exist.") >> exitFailure
+  True → do
+    let f p = run <$> fetchAllTaggedPosts p XML xs
+          where
+            run s =
+              fromList [ (md5 `rGet` r, file_url `rGet` r) | Right r ← s ]
+    g ← f Gelbooru
+    i ← f Ichijou
+    k ← f Konachan
+    s ← f Safebooru
+    y ← f Yandere
+    let ls = g <> i <> k <> s <> y
+        mkFp (m, u) = let e = snd $ splitExtension u
+                      in fp </> m <.> e
+    dcs ← Prelude.map (fp </>) <$> getDirectoryContents fp
+    let notInFiles = (`notElem` dcs) . snd
+        fs = Prelude.filter notInFiles [ (snd x, mkFp x) | x ← assocs ls ]
+        lfs = show $ length fs
+    ds ← atomically newTChan
+    got ← newTVarIO 0
+    let loop = atomically (readTChan ds) >>= \case
+          EndOfQueue → putStrLn "Done."
+          x → do
+            v ← atomically $ modifyTVar got succ >> readTVar got
+            putStrLn (concat ["(", show v, "/", lfs, "): ", show x]) >> loop
+
+    void . forkIO $ downloadFiles fs ds 5
+    loop
+
+
+-- | Fetches a map of images, with keys being the md5 and values being
+-- URLs.
+fetchImageLinks ∷ [Tag] → IO [Parse String]
 fetchImageLinks xs = do
-  let f p = map (file_url `rGet`) <$> fetchAllTaggedPosts p XML xs
+  let f p = Prelude.map getInfo <$> fetchAllTaggedPosts p XML xs
+        where
+          getInfo (Left (PF m)) = Left . PF $ unwords [show p, m]
+          getInfo (Right r) = return $ file_url `rGet` r
   g ← f Gelbooru
   i ← f Ichijou
   k ← f Konachan
   s ← f Safebooru
   y ← f Yandere
-  let ls = g ++ i ++ k ++ s ++ y
+  let ls = g <> i <> k <> s <> y
   return $ length ls `seq` ls
 
 help ∷ String
 help = unlines $
-       [ "Usage: h-booru tag1 [tag2] … [tagn]"
-       , ""
-       , "Prints a list of links matching the tags"
-       ]
+  [ "Usage: h-booru tag1 [tag2] … [tagN]"
+  , ""
+  , "Prints a list of links matching the tags"
+  , ""
+  , "h-booru -d DIRECTORY tag1 [tag2] … [tagN]"
+  , ""
+  , "Downloads the files with the given tags to the given directory."
+  , "Naming scheme is md5.originalextension"
+  , "The dowloader will skip files it already sees downloaded, by filename."
+  ]