I'm using the graph api endpoint /PAGE_ID/posts to get all posts from a facebook page.
Now I want the full sized image from these posts. The picture property of the returned objects gives me only a cropped version of that image.

With the object id from these posts and the API endpoint /OBJECT_ID/picture I get the only the small, normal and album sized version of the picture. But with a little modification to the URL I managed to get the full sized image.

Example

This URL:

https://graph.facebook.com/10152843929471041/picture

redirects to this URL:

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/s720x720/10838228_10152843929471041_5251228402651650719_n.jpg

I removed the 720x720 from that URL to get this URL:

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/s/10838228_10152843929471041_5251228402651650719_n.jpg

which is finally the full sized image.

I think, that I can achieve this modification with a regex pattern. But now is my question, how I can get the URL after the redirect from the original URL (the first one).

Any ideas or simpler solutions?