Very new feature, Facebook releases a new Photo Viewer title Theater. Nothing very special about this view except it's new ^^. At this time, it seems very buggy (I think it's beeing deployed through cache servers) but you could see a nice preview...
No more need to go in the Photo page to see it, the Theater is directly available from your home stream.
Just discovered too: there is no more « Send » button to post comments. Press
Enter key to submit!
Under Photos link in your sidebar, you could see a new link « Memories » which allows you to browse into you Facebook activity since you joined. Very fun to get information about how many updates did you submit in 2007 for example.
Here a screenshot :