diff --git a/README.md b/README.md
index 0da0ef6..dc52f98 100644
--- a/README.md
+++ b/README.md
@@ -16,9 +16,9 @@ use bitsy_parser::image::Image;
 /// replaces the player avatar with a smiley face.
 fn main() {
     let input_file = env::args().nth(1)
-        .expect("No game data specified. Usage: `invert infile outfile`");
+        .expect("No game data specified. Usage: `smiley infile outfile`");
     let output_file = env::args().nth(2)
-        .expect("No game data specified. Usage: `invert infile outfile`");
+        .expect("No game data specified. Usage: `smiley infile outfile`");
 
     let mut game = Game::from(fs::read_to_string(input_file).unwrap());