使用必应源，每次随机切换图片
api如下
随机 https://api.i-meto.com/bing
最新图片 https://api.i-meto.com/bing?new
红色风格 https://api.i-meto.com/bing?color=Red
黑色风格 https://api.i-meto.com/bing?color=Black
白色风格 https://api.i-meto.com/bing?color=White
动物分类 https://api.i-meto.com/bing?cat=A
旅行分类 https://api.i-meto.com/bing?cat=T
空中分类 https://api.i-meto.com/bing?cat=S
api接口来源于萨摩公园
刷新页面查看效果