The Photo page now makes the photo the clear focus. The ratings, view counts, and social sharing information have been pushed to the top of the page. The exposure information, tags, caption, and comments reside under the photo.
That leaves the actual image in the middle of the page, without any clutter surrounding it. Double clicking on it brings up the slideshow functionality, which is actually fairly similar to a Flickr page, but is laid out more intelligently with controls for moving around the gallery.
They just rolled it out, but the pages seem to be moving rather quickly, which is nice. It's a clean look and a clear indicator that 500PX noticed Flickr taking some of their design inspiration.