Attempt to get the new location for the high res images from posts

Facebook has changed the location for high res photos. It a lot of cases you can simply remove a part of the URL in the form

/s130x130/

However, this isn't always the case. I've seen some URLs with a /q80/ part that is needed and sometimes the sXXXxXXX needs replacing with a different value.

This is why there's a test on the headers of the new URL before setting it as the photo. If the headers don't return a 200 response then the original image returned from Facebook is used.