message: Fix offset calculation
diff: @@ -117,11 +117,9 @@ impl<W: Write> IcoEncoder<W> {
  }
  let num_images = images.len() as u16;
  - let mut offset = ICO_ICONDIR_SIZE;
  + let mut offset = ICO_ICONDIR_SIZE + (ICO_DIRENTRY_SIZE * (images.len() as u32));
  write_icondir(&mut self.w, num_images)?;
  for image in images {
  - offset += ICO_DIRENTRY_SIZE;
  -
  write_direntry(
  &mut self.w,
  image.width,
  