If you compare the two links, you'll see that the sequence "kb20050519010507" is the same in both. That is the actual image id, and it will always stay the same. Thus, it makes no difference permanence-wise if you copy one link or the other.
The Digitalarkivet at first had a link system that showed obvious weaknesses after some time, and it was replaced some years ago with the present one. There's no reason to believe that the current system will be changed anytime soon. And, in any case, the image id will always be preserved and be accessible in some form.