diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,5 @@
 # Revision history for window-utils
 
-## 0.1.0.0 -- 12-03-2023
+## 0.2.1.0 -- 03-04-2023
 
-* First version. Released on an unsuspecting world.
+* Handle PNGs with no alpha channel.
diff --git a/src/OS/Window/X11.hs b/src/OS/Window/X11.hs
--- a/src/OS/Window/X11.hs
+++ b/src/OS/Window/X11.hs
@@ -7,6 +7,7 @@
 
 import Codec.Picture
 import Control.Applicative
+import Control.Arrow
 import Data.Bits
 import Data.ByteString (ByteString)
 import Data.ByteString qualified as BS
@@ -51,25 +52,43 @@
     -- | PNG image
     ByteString ->
     IO ()
-setIcon (Window w d) img = do
-    case decodePng img of
-        Left e -> error e
-        Right (ImageRGBA8 Image{..}) -> do
-            nET_WM_ICON <- internAtom d "_NET_WM_ICON" True
-            changeProperty32 d w nET_WM_ICON cARDINAL propModeReplace $
-                map fromIntegral [imageWidth, imageHeight]
-                    ++ map fromIntegral (groupPixels $ Vec.toList imageData)
-            flush d
-          where
-            groupPixels :: [Word8] -> [Word64]
-            groupPixels = \case
-                r : g : b : a : ps ->
-                    ( shift (fromIntegral a) 24
-                        .|. shift (fromIntegral r) 16
-                        .|. shift (fromIntegral g) 8
-                        .|. shift (fromIntegral b) 0
-                    )
-                        : groupPixels ps
-                [] -> []
-                _ -> error "vector length not a multiple of 4"
-        _ -> error "wrong pixel type"
+setIcon (Window w d) =
+    decodePng >>> either error \case
+        ImageRGBA8 Image{..} -> rgb imageWidth imageHeight imageData \case
+            r : g : b : a : ps -> Just ((r, g, b, a), ps)
+            [] -> Nothing
+            _ -> error "vector length not a multiple of 4"
+        ImageRGB8 Image{..} -> rgb imageWidth imageHeight imageData \case
+            r : g : b : ps -> Just ((r, g, b, maxBound), ps)
+            [] -> Nothing
+            _ -> error "vector length not a multiple of 3"
+        ImageY8{} -> error "unexpected pixel type: ImageY8"
+        ImageY16{} -> error "unexpected pixel type: ImageY16"
+        ImageY32{} -> error "unexpected pixel type: ImageY32"
+        ImageYF{} -> error "unexpected pixel type: ImageYF"
+        ImageYA8{} -> error "unexpected pixel type: ImageYA8"
+        ImageYA16{} -> error "unexpected pixel type: ImageYA16"
+        ImageRGB16{} -> error "unexpected pixel type: ImageRGB16"
+        ImageRGBF{} -> error "unexpected pixel type: ImageRGBF"
+        ImageRGBA16{} -> error "unexpected pixel type: ImageRGBA16"
+        ImageYCbCr8{} -> error "unexpected pixel type: ImageYCbCr8"
+        ImageCMYK8{} -> error "unexpected pixel type: ImageCMYK8"
+        ImageCMYK16{} -> error "unexpected pixel type: ImageCMYK16"
+  where
+    rgb :: Int -> Int -> Vec.Vector Word8 -> ([Word8] -> Maybe ((Word8, Word8, Word8, Word8), [Word8])) -> IO ()
+    rgb imageWidth imageHeight imageData unconsPixels = do
+        nET_WM_ICON <- internAtom d "_NET_WM_ICON" True
+        changeProperty32 d w nET_WM_ICON cARDINAL propModeReplace $
+            map fromIntegral [imageWidth, imageHeight]
+                ++ map fromIntegral (groupPixels $ Vec.toList imageData)
+        flush d
+      where
+        groupPixels :: [Word8] -> [Word64]
+        groupPixels =
+            unconsPixels >>> maybe [] \((r, g, b, a), ps) ->
+                ( shift (fromIntegral a) 24
+                    .|. shift (fromIntegral r) 16
+                    .|. shift (fromIntegral g) 8
+                    .|. shift (fromIntegral b) 0
+                )
+                    : groupPixels ps
diff --git a/window-utils.cabal b/window-utils.cabal
--- a/window-utils.cabal
+++ b/window-utils.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               window-utils
-version:            0.2.0.0
+version:            0.2.1.0
 license:            BSD-3-Clause
 author:             George Thomas
 maintainer:         georgefsthomas@gmail.com
@@ -34,10 +34,10 @@
         cpp-options:
             -DWIN=Unsupported
     build-depends:
-        base ^>= 4.16,
+        base ^>= {4.16, 4.17, 4.18},
         bytestring ^>= 0.11,
         JuicyPixels ^>= 3.3.6,
-        text ^>= 1.2.3,
+        text ^>= {1.2.3, 2.0},
         vector ^>= 0.12.3.1,
     default-language: GHC2021
     default-extensions: