We have seen many twitter desktop clients that work as facebook client too, but you can only view and post status messages through them. If you want to upload photos, chat with friends, etc then you will need to install a proper desktop facebook client.
Recently Adobe Marketplace has released Photo Uploader For Facebook, a cross-platform adobe air app. Unlike the name says, it is actually much more than a simple photo uploader for facebook. In other words, it is one complete desktop Facebook client.
Once connected to facebook, you will find the complete layout which is similar to Facebook, you can access your profile, check upcoming events, view photos, chat with friends who are online, and do much more.
It contains a new separate tab called Upload. This tab allows you to quickly upload photos to facebook straight from your desktop. In case you are looking for an alternative, have a look at RightLoad and LiveUpload.
Even though it can come useful, it also has some downsides. You cannot send a message to your friend, nor is the news feed updated live, you cannot check Inbox from within app, and some other restricted functionalities.
It is a cross-platform app that works on Windows, Mac, and Linux. Enjoy!