我这是把公众号授权给第三方了
三方appid：wx468d613169be627d
公众号appid：wx6acaca3f47dbd72c
media_id：zvC84m-NU7JTc32sSBbKdaJE3l_IkTbULH7JqskYniXh1gOAfEF0KwftwJ4N83dp

先将图片上传到临时素材得到的media_id

发送客服消息数据：{"touser":"","msgtype":"image","image":{"media_id":"zvC84m-NU7JTc32sSBbKdaJE3l_IkTbULH7JqskYniXh1gOAfEF0KwftwJ4N83dp"}}
调用接口：https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=$authorizer_access_token