Your PHP script should have you login. If the login was successful, the SDK will manage the access_token for you.
Then issue this one request:
$result = $this->facebook->api('/me/accounts?fields=name,picture.type(large)', 'GET');
If you don't want to authenticate, instead you can pass an array of ids:
$page_ids = array( _PAGE_ID_1, _PAGE_ID_2, ...);
$result = $this->facebook->api('/?ids=' . implode(',',$page_ids) . '&fields=name,picture.type(large)', 'GET');
For these queries, you are getting data, so you should be using a GET
request. Within the Facebook API, POST
requests are only used when you are sending data to Facebook.