Index: applications/editors/josm/plugins/wmsplugin/webkit-image.cpp
===================================================================
--- applications/editors/josm/plugins/wmsplugin/webkit-image.cpp	(revision 11979)
+++ applications/editors/josm/plugins/wmsplugin/webkit-image.cpp	(revision 11986)
@@ -43,5 +43,6 @@
         for(int y = 0; iswhite && y < ysize; ++y)
         {
-          if(im.pixel(x, y) != white)
+          QRgb p = im.pixel(x, y);
+          if(p != white && p)
             iswhite = false;
         }
@@ -54,5 +55,6 @@
         for(int x = 0; iswhite && x < xsize; ++x)
         {
-          if(im.pixel(x, y) != white)
+          QRgb p = im.pixel(x, y);
+          if(p != white && p)
             iswhite = false;
         }