图片加载异常同时显示alt图像信息实例页面

CSS代码：

img {
  display: inline-block;
  transform: scale(1);
}
img::before {
  content: '';
  position: absolute;
  left: 0; top: 0;
  width: 100%; height: 100%;
  background: #f5f5f5 url(break.svg) no-repeat center / 50% 50%;
  color: transparent;
}
img::after {
  content: attr(alt);
  position: absolute;
  left: 0; bottom: 0;
  width: 100%;
  line-height: 2;
  background-color: rgba(0,0,0,.5);
  color: white;
  font-size: 12px;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

HTML代码：

<img src="street.jpg" alt="街道">
<img src="zxx.jpg" alt="CSS新世界封面" onerror="this.classList.add('error');">
<img src="moon-night.jpg" alt="夜景星空">