必应每天都会更换一张漂亮的照片作为首页背景图：
https://s1.ax1x.com/2020/11/09/BbUNxf.png

分析必应API返回的JSON

必应的API就是这个：

https://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1

访问后可以看到它返回了一串json

{
    "images": [{
        "startdate": "20201109",
        "fullstartdate": "202011090800",
        "enddate": "20201110",
        "url": "/th?id=OHR.PiedmontRegion_EN-CN9491375405_1920x1080.jpg&rf=LaDigue_1920x1080.jpg&pid=hp",
        "urlbase": "/th?id=OHR.PiedmontRegion_EN-CN9491375405",
        "copyright": "The hills of Barolo vineyards in Piedmont, Italy (© Marco Arduino/eStock Photo)",
        "copyrightlink": "https://www.bing.com/search?q=piedmont+italy&form=hpcapt&filters=HpDate%3a%2220201109_0800%22",
        "title": "Autumn in Piedmont",
        "quiz": "/search?q=Bing+homepage+quiz&filters=WQOskey:%22HPQuiz_20201109_PiedmontRegion%22&FORM=HPQUIZ",
        "wp": true,
        "hsh": "7a0098e878a14a5c6e88b8696355924a",
        "drk": 1,
        "top": 1,
        "bot": 1,
        "hs": []
    }],
    "tooltips": {
        "loading": "Loading...",
        "previous": "Previous image",
        "next": "Next image",
        "walle": "This image is not available to download as wallpaper.",
        "walls": "Download this image. Use of this image is restricted to wallpaper only."
    }
}

很明显url就是我们需要的图片路径，下面我们就可以开始制作我们自己的API了

编写API

@header("Content-Type:image/png");   //设置头为图片

$data = json_decode(file_get_contents("https://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1"),true);   //获取api返回的json，并解析成数组

echo file_get_contents('https://www.bing.com'.$data['images'][0]['url']);

这样我们就成功获得了一个获取每日一图的API，
但是这个api只能获取1920px*1080px的图片，很多时候我们需要其它尺寸的图片

我们把api修改一下，这次我们使用urlbase，自己设置图片尺寸：

@header("Content-Type:image/png");   //设置头为图片

$size = "1080x1920";   //设置图片尺寸

$data = json_decode(file_get_contents("https://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1"),true);   //获取api返回的json，并解析成数组

echo file_get_contents('https://www.bing.com'.$data['images'][0]['urlbase'].'_'.$size.'.jpg');

这样我们通过修改size值来控制图片尺寸的大小

我的API

https://api.miri.site/getbing/
你可以在URL末加上图片尺寸获取对应尺寸的每日一图：

https://api.miri.site/getbing/1920x1080 ：
GetBing 1920x1080

https://api.miri.site/getbing/640x480 ：
GetBing 640x480