為什麼我的圖像居中對齊，但不兩端對齊？我很困惑..

<Box
      sx={{
        display: 'flex',
        minHeight: '100vh',
        alignItems: 'center',
        flexGrow: 1,
      }}>
      <Container maxWidth="sm">
        <img src="https://static.vecteezy.com/system/resources/previews/001/200/294/original/house-png.png"
          width={200}
          alt="img"
        />
        <LinearProgress sx={{ mt: 4 }} />
      </Container>
    </Box>