When you try to access a Picasa Web Album that belongs to a Google+ user, it redirects to the Google+ Photos page for it. There is an option in a yellow banner at the top to go back to the PWA page.

Test: http://picasaweb.google.com/mrrix32
https://lh5.googleusercontent.com/-tYvBban2FJM/T8Cr3buvXvI/AAAAAAAAPuQ/vONuR1dx6cs/s640/PWA.png

Admittedly I rarely visited PWA, and I suppose this was inevitable. Although how are you meant to upload larger photos? (If they totally remove PWA)

Note: While writing this post, I visited PWA and it didn't redirect to G+, maybe they're just testing?