Facebook keeps introducing changes to certain parts of their system off and on. The latest change brought about by Facebook is their revamped photo viewer. I was just checking out Facebook and noticed the new photo viewer. The photo viewer has gone through many changes in the past. I am sure you will like this new light box photo viewer.
I must say Facebook more or less borrowed the concept from the Photo Viewer on Google Plus. When you click a photo, it opens up in a lightbox with the photo itself on the left and the comments on the right. A similar layout is prevalent in Google Plus Photo Viewer where the comments appear side by side with the respective photo.
You can find the like button just beneath a photo after hovering over it. At the top of the comments pane, you can find options for either downloading or reporting any photo. The new Facebook Photo Viewer seems to have fixed the issues on the earlier viewer. If you were viewing photos from two different albums, the photos would get mixed up in the viewer. I have faced this issue a couple of times on Facebook. I hope the new Facebook photo viewer has solved it.