If you use filters and layers in adobe photoshop, you do not need to edit every image in an animation. You can create different layers for the different stages and in the animation choose which layers get shown in what frame of the animation. So as long as you don't touch the scrolling text all you need to touch are layers that can be in every frame.
I actually remade the images a while back (needed them in "brown" instead of "blue"), but I'm not so sure the phpBB team at large wants them to be distributed, so unless I hear they are OK with distributing these lookalike ripoffs, I'm not distributing.
BTW mine are partial bitmap, partial vector.
Looking at how the distributed images are, rest assured that they've not been made all in the same manner, so there's not going to be a master file they've misplaced.