抖音直播竖屏截图：主播举牌画面

9:16 的图片比例，生成一张抖音直播的截图，里面是 xxx 在直播，xxx 手里拿着牌子，牌子里写着 xxxx。

9:16 aspect ratio, generate a screenshot of a Douyin live stream, inside is xxx live streaming, xxx is holding a sign in their hand, the sign says xxxx.