diff --git a/Changelog b/Changelog
index 4047b6f..f438af4 100644
--- a/Changelog
+++ b/Changelog
@@ -1,3 +1,9 @@
+2003-09-30  Henning Meier-Geinitz <henning@meier-geinitz.de>
+
+	* src/xscanimage.c: Make sure that we save only to files with
+	  extension pnm (and similar). Patch from Gerard Klaver
+	  <gerard@gkall.hobby.nl>, bug #300239.
+
 2003-09-24  Henning Meier-Geinitz <henning@meier-geinitz.de>
 
 	* README doc/scanadf.man: Changed links to
diff --git a/src/xscanimage.c b/src/xscanimage.c
index 4256502..3e862aa 100644
--- a/src/xscanimage.c
+++ b/src/xscanimage.c
@@ -1206,9 +1206,28 @@ static void
 scan_dialog (GtkWidget * widget, gpointer call_data)
 {
   char buf[256];
+  char testfilename[256];
   
   if (scan_win.mode == STANDALONE)
     {				/* We are running in standalone mode */
+      				/* test for pnm formats*/
+      strncpy (testfilename, preferences.filename, sizeof (testfilename));
+      testfilename [sizeof (testfilename)] = 0;
+      g_strreverse (testfilename);
+      if (! ((!strncmp(testfilename,"mnp.",4)) || 
+	     (!strncmp(testfilename,"mgp.",4)) ||
+	     (!strncmp(testfilename,"mbp.",4)) ||
+	     (!strncmp(testfilename,"mpp.",4)) ||
+	     (!strncmp(testfilename,"MNP.",4)) || 
+	     (!strncmp(testfilename,"MGP.",4)) ||
+	     (!strncmp(testfilename,"MBP.",4)) ||
+	     (!strncmp(testfilename,"MPP.",4)) ))
+	{
+	  snprintf (buf, sizeof (buf), "Failed to scan, wrong file extension, use pnm, pgm, pbm or ppm `%s'",
+		    preferences.filename);
+	  gsg_error (buf);
+	  return;
+	}
       scan_win.out = fopen (preferences.filename, "w");
       if (!scan_win.out)
 	{