这个接口api.weixin.qq.com/cgi-bin/material/get_material?access_token=ACCESS_TOKEN

应该返回{
 "news_item":
 [
     {
     "title":TITLE,
     "thumb_media_id":THUMB_MEDIA_ID,
     "show_cover_pic":SHOW_COVER_PIC(0/1),
     "author":AUTHOR,
     "digest":DIGEST,
     "content":CONTENT,
     "url":URL,
     "content_source_url":CONTENT_SOURCE_URL
     },
     //多图文消息有多篇文章
  ]
}
但是却直接返回我上传的图片了, 我想获取发送客服消息的thumb_media_id怎么办?