I am trying to post photos from my Windows 7.1 mobile app into the user's timeline.
How can I do so?
You may take a look on Facebook C# SDK which now supports Windows Phone. I think to see a photo in timeline it is enough to upload it. If you were referring to information in the past, I believe it is not possible with current Api.
Photo Upload working sample code
http://igrali.com/2012/06/07/share-photos-on-facebook-from-windows-phone-app/ http://facebooksdk.blogspot.com/2011/04/facebook-album.html
Interesting thread with additional discussion and examples