I've emailed OpenPhoto support about this directly. This is in reference to their hosted option at openphoto.me - thumbnails are generated and stored on a central server, so the permalinks to the thumbnails are not generated or stored on your domain. Leading to the exact same issue of not owning your permalinks as is the case on Flickr today. Until this is changed, there is little point to switching.
I think Steve's post sums it up the best: I really do want to support great user-supported web services, and Flickr is an example of one of them.