diff --git a/src/calibre/ebooks/lrf/comic/convert_from.py b/src/calibre/ebooks/lrf/comic/convert_from.py
index eef7d4cb43..48d19657d0 100755
--- a/src/calibre/ebooks/lrf/comic/convert_from.py
+++ b/src/calibre/ebooks/lrf/comic/convert_from.py
@@ -180,7 +180,7 @@ class PageProcessor(list):
                 
             MagickSetImageType(wand, GrayscaleType)
             MagickQuantizeImage(wand, self.opts.colors, RGBColorspace, 0, 1, 0)
-            dest = '%d_%d%s'%(self.num, i, os.path.splitext(self.path_to_page)[-1])
+            dest = '%d_%d.png'%(self.num, i)
             dest = os.path.join(self.dest, dest)
             MagickWriteImage(wand, dest)
             self.append(dest)
@@ -335,4 +335,4 @@ def main(args=sys.argv, notification=None):
     return 0
 
 if __name__ == '__main__':
-    sys.exit(main())
\ No newline at end of file
+    sys.exit(main())
diff --git a/src/calibre/gui2/dialogs/config.py b/src/calibre/gui2/dialogs/config.py
index c84c3a3713..dd34aba10d 100644
--- a/src/calibre/gui2/dialogs/config.py
+++ b/src/calibre/gui2/dialogs/config.py
@@ -13,7 +13,6 @@ from calibre.gui2.widgets import FilenamePattern
 from calibre.ebooks import BOOK_EXTENSIONS
 
 
-
 class ConfigDialog(QDialog, Ui_Dialog):
     
     def __init__(self, window, db, columns):
@@ -98,7 +97,7 @@ class ConfigDialog(QDialog, Ui_Dialog):
         config['show_text_in_toolbar'] = bool(self.show_toolbar_text.isChecked())
         config['confirm_delete'] =  bool(self.confirm_delete.isChecked())
         pattern = self.filename_pattern.commit()
-        config['filename_pattern'] = pattern
+        prefs['filename_pattern'] = pattern
         config['save_to_disk_single_format'] = BOOK_EXTENSIONS[self.single_format.currentIndex()]
         config['cover_flow_queue_length'] = self.cover_browse.value()