--- a/PNGReader.st	Thu Sep 20 09:48:06 2018 +0200
+++ b/PNGReader.st	Mon Sep 24 10:42:58 2018 +0200
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 1996 by Claus Gittinger
               All Rights Reserved
@@ -1702,17 +1700,18 @@
         paletteIndexForMaskedPixels := freePixels first.
     ].    
 
-    "/ rewrite data: wherever masked, change pixel to paletteIndexForMaskedPixels
-    
-    data := data copy.
-    pixelIdx := 1.
-    0 to:height-1 do:[:y |
-        0 to:width-1 do:[:x |
-            (mask pixelAtX:x y:y) == 0 ifTrue:[
-                data at:pixelIdx put:paletteIndexForMaskedPixels.
-            ].
-            pixelIdx := pixelIdx + 1
-        ]
+    depth == 8 ifTrue:[
+        "/ rewrite data: wherever masked, change pixel to paletteIndexForMaskedPixels
+        data := data copy.
+        pixelIdx := 1.
+        0 to:height-1 do:[:y |
+            0 to:width-1 do:[:x |
+                (mask pixelAtX:x y:y) == 0 ifTrue:[
+                    data at:pixelIdx put:paletteIndexForMaskedPixels.
+                ].
+                pixelIdx := pixelIdx + 1
+            ]
+        ].
     ].
     
     "       
@@ -1722,6 +1721,7 @@
 
     "Created: / 16-02-2017 / 19:59:39 / cg"
     "Modified: / 17-02-2017 / 09:25:57 / cg"
+    "Modified: / 24-09-2018 / 10:39:34 / Claus Gittinger"
 ! !
 
 !PNGReader methodsFor:'writing-private chunks'!