Clarify that the background is always an image file

diff --git a/README.menu b/README.menu
index 71d32e5..3cfeaca 100644 (file)
--- a/README.menu
+++ b/README.menu
@@ -289,16 +289,16 @@ MENU VSHIFT 0
        screen (25 for text mode, 28 for VESA graphics mode.)
 
 
-F1 textfile background
+F1 textfile background_file
 ...
-F12 textfile background
+F12 textfile background_file
 
        Displays full-screen help (also available at the command line.)
        The same control code sequences as in the command line
        interface are supported, although some are ignored.
 
        Additionally, a second argument allows a different background
-       image to be displayed.
+       image file (see MENU BACKGROUND) to be displayed.
 
 
 The menu system honours the TIMEOUT command; if TIMEOUT is specified