s_img[:, :, (c)] * (s_img[:, :, (3)] / 255.0) + l_img[y_offset:y_offset +
    s_img.shape[0], x_offset:x_offset + s_img.shape[1], (c)] * (1.0 - s_img
    [:, :, (3)] / 255.0)
overlay a smaller image on a larger image python OpenCv