--- a/Depth1Image.st	Mon Jun 11 10:50:04 2018 +0100
+++ b/Depth1Image.st	Wed Jul 11 16:58:29 2018 +0200
@@ -1,5 +1,6 @@
 "
  COPYRIGHT (c) 1993 by Claus Gittinger
+ COPYRIGHT (c) 2018 Patrik Svestka
 	      All Rights Reserved
 
  This software is furnished under a license and may be used
@@ -683,6 +684,14 @@
     ^ super colorFromValue:pixelValue.
 !
 
+isDepth1Image
+    "return true if the image is instance of Depth1Image"
+   (self bitsPerPixel == 1) ifTrue:[^ true].  
+    ^ false
+
+    "Created: / 16-04-2018 / 17:02:34 / svestkap"
+!
+
 rgbFromValue:pixelValue
     "given a pixel value, return the corresponding 24bit rgbValue (rrggbb, red is MSB).
      Pixel values start with 0."