我正在使用Facebook Graph API来获取公共页面上的帖子 . 我正在使用此网址：

https://graph.facebook.com/v2.6/jogging.international/posts?fields=id,type,created_time,link,message,source,object_id,picture,full_picture&limit=10&access_token=XXXX

对于“链接”帖子，像这样：

{
     "id": "58027708919_10153766074838920",
     "type": "link",
     "created_time": "2016-06-07T12:00:00+0000",
     "link": "http://po.st/Piscine",
     "message": "La natation pour optimiser vos entra\u00eenements?!? Pourquoi? Comment?\nNos 6 mani\u00e8res de l'inclure dans vos programmes !! \ud83c\udf0a \ud83d\udcaa  \ud83c\udfc3",
     "picture": "https://external.xx.fbcdn.net/safe_image.php?d=AQDSc30G8WnJJrnb&w=130&h=130&url=fbstaging\u00253A\u00252F\u00252Fgraph.facebook.com\u00252Fstaging_resources\u00252FMDExMDE1Mzc2NjA2Njc4ODkyMDoyMTMwMzk2MjE4&cfs=1",
     "full_picture": "https://external.xx.fbcdn.net/safe_image.php?d=AQAKv_-jfO40xDvY&url=fbstaging\u00253A\u00252F\u00252Fgraph.facebook.com\u00252Fstaging_resources\u00252FMDExMDE1Mzc2NjA2Njc4ODkyMDoyMTMwMzk2MjE4"
  },

picture和full_picture URL返回1x1 px图像 . 这是正常的吗？如果是这样，我怎么能得到Facebook生成的缩略图？

facebook-graph-api