一般来说，如果你想收集一个用户或页面，图标大小图片的格式为：

  http://graph.facebook.com/ [页面ID / profile id] / picture 
 

和大图：

  http://graph.facebook.com/ [page id / profile id] / picture？type = large 
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 编辑要点：$ b​​ $ b如果保存在Facebook服务器上的图像小于200 * 200的尺寸，您将获得图像作为最高分辨率，例如：128 * 160。您可以使用GD库调整大小。
 

 另一个更重要 
 

 Facebook支持200 * 600像素作为配置文件图片的最高分辨率。 
 

  *截至2017年2月19日的更新*  
 > 

我们需要使用这个新的URL格式来获取所需的配置文件图像。 
  http://graph.facebook.com/ {profile_id} / picture？width = {number}& height = {number} 
 
 [谢谢 https://***.com/users/2829128/vay]  
 
I am getting an image from facebook by the URL: http://external.ak.fbcdn.net/safe_image.php?d=d282e1e7c86c9270232f97ddc737df39&w=90&h=90&url=http%3A%2F%2Fi52.tinypic.com%2F2q0ixzl.jpg

Now, I want a bigger version, like 200 by 200. Is there a URL for that? If not, how can I convert this image to a larger size?
Generally if you want to collect the profile pic of a user or page, the format for the icon size picture is:
http://graph.facebook.com/[page id/profile id]/picture
and for the large picture:
http://graph.facebook.com/[page id/profile id]/picture?type=large
EDIT Points to note:
If the image stored on the facebook servers is less than the 200*200 dimensions, you would get the image as the highest resolution avaiable eg: 128*160. Either you can resize it using the GD library.

AND ONE MORE THING

Facebook supports 200*600px as the highest resolution for the profile pic. It will resize an image to fit into these dimensions by maintaining the aspect ratio.

*UPDATE as on 19th Feb, 2017 *

We need to use this new URL formation to get a desired profile image. 
http://graph.facebook.com/{profile_id}/picture?width={number‌​}&height={number}
[Thank you https://***.com/users/2829128/vay]