diff --git a/src/main.rs b/src/main.rs
index 5881f5b..8877c32 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -121,7 +121,7 @@ use image::ColorType;
 
 /// Write the buffer `pixels`, whose dimensions are given by `bounds`, to the
 /// file named `filename`.
-fn write_bitmap(filename: &str, pixels: &[u8], bounds: (usize, usize))
+fn write_image(filename: &str, pixels: &[u8], bounds: (usize, usize))
     -> Result<()>
 {
     let output = try!(File::create(filename));
@@ -192,5 +192,5 @@ fn main() {
             });
     }
 
-    write_bitmap(&args[1], &pixels, bounds).expect("error writing PNG file");
+    write_image(&args[1], &pixels, bounds).expect("error writing PNG file");
 }