note about counter-clockwise rotation

src/image.rs

@@ -36,6 +36,7 @@ impl Image {
 
         // start from bottom-left corner, work upward in that column,
         // then work on the next column to the right
+        // for counter-clockwise, just reverse x instead of y
         for x in 0..8 {
             for y in (0..8).rev() {
                 pixels.push(self.pixels[(y * 8) + x]);