--- a/Image.st	Sun Feb 19 15:10:45 2017 +0100
+++ b/Image.st	Mon Feb 20 11:02:27 2017 +0100
@@ -14275,17 +14275,29 @@
 
     |usedValues max colors|
 
-    photometric == #rgb ifTrue:[
+    (photometric == #rgb or:[photometric == #rgba]) ifTrue:[
         usedValues := IdentitySet new.
-        self valuesFromX:0 y:0 toX:(width-1) y:(height-1)
-          do:[:x :y :pixel |
-            usedValues add:pixel.
-            usedValues size > nMax ifTrue:[
-                "/ too many to be returned here (think of the mass of
-                "/ data to be returned by a 24bit image ... ;-)
-                ^ nil
-            ]
-        ].
+        (photometric == #rgb) ifTrue:[
+            self valuesFromX:0 y:0 toX:(width-1) y:(height-1)
+              do:[:x :y :pixel |
+                usedValues add:pixel.
+                usedValues size > nMax ifTrue:[
+                    "/ too many to be returned here (think of the mass of
+                    "/ data to be returned by a 24bit image ... ;-)
+                    ^ nil
+                ]
+            ].
+        ] ifFalse:[
+            self valuesFromX:0 y:0 toX:(width-1) y:(height-1)
+              do:[:x :y :pixel |
+                usedValues add:(pixel bitShift:-8).
+                usedValues size > nMax ifTrue:[
+                    "/ too many to be returned here (think of the mass of
+                    "/ data to be returned by a 24bit image ... ;-)
+                    ^ nil
+                ]
+            ].
+        ].    
 "/        colors := usedValues collect:[:pixel | self colorFromValue:pixel].
         "/ this code is slightly faster (but wrong for 16-bit images)...
         colors := usedValues collect:[:pixel | 
@@ -14318,8 +14330,8 @@
      (Image fromFile:'libtool/bitmaps/SBrowser.xbm') usedColors
     "
 
-    "Created: / 7.9.1998 / 17:54:17 / cg"
-    "Modified: / 7.9.1998 / 17:56:21 / cg"
+    "Created: / 07-09-1998 / 17:54:17 / cg"
+    "Modified: / 20-02-2017 / 10:57:17 / cg"
 !
 
 usedValues