diff --git a/tests/image/image.cpp b/tests/image/image.cpp
index 8d7dae6ce1..8782d95a24 100644
--- a/tests/image/image.cpp
+++ b/tests/image/image.cpp
@@ -976,9 +976,7 @@ void ImageTestCase::CompareSavedImage()
     CPPUNIT_ASSERT( expected24.IsOk() );
     CPPUNIT_ASSERT( !expected24.HasAlpha() );
 
-    unsigned long numColours = expected24.CountColours();
     wxImage expected8 = expected24.ConvertToGreyscale();
-    numColours = expected8.CountColours();
 
 #if wxUSE_PALETTE
     unsigned char greys[256];