If you are new to C# SDK, you can start from here: Facebook SDK for .NET
Concept
You can get the feeds from a page using:
/PAGE_ID/feed
You can get the photos from a page using:
/PAGE_ID/photos
(only if the feeds/photos are public)
Implementation
Example-
FacebookClient fb = new FacebookClient(App.AccessToken);
dynamic parameters = new ExpandoObject();
parameters.access_token = App.AccessToken;
dynamic result = await fb.GetTaskAsync("PAGE_ID/feed", parameters);
Graph API Explorer Examples-
You can get the parameters you required.