Not only both files are identical, but also are RGB, 2 layers.
Incorrect, your .16.png file, unzipped from your first post is 8 bit indexed, the original (in my media folder) is rgba.
My GIMP shows RGB, 2 layers, you have it on the screenshot.
In your gimp left one is "indexed, 1 layer" and right one is "RGB, 1 layer". But we are talking about same files... Which version do you have? Did you tried another program ?
I added proof that alfa works.
Incorrect again, you proved that transparency worked, by specifying in the palette that the first colour index should not be drawn (i.e. transparent).
But as DaleStan stated, you cannot specify the alfa value, i.e. make something 50% transparent. And exactly that is used in the originals to do some anti-aliasing on the edges. Because you can only specify 0% or 100% transparency, the edges will look jaggy.
If you have right, why both images look identical (which I shown already), including transparency - in this thread, in my GIMP, in my Paint.net ? I dont't know technically what was changed, I know, that files are smaller and look identical. No anti-aliasing is lost, which you can see in this thread - maybe it is lost in old GIMP version. Of course, DEVs should have backup of original files, but I think, that distributable version should be the optimized one.
Also i checked transparency - it is >0 and <100
By the way, I have two questions:
1) Where are these PNGs used? I know, that these files are stored in \media\ but where in game?
2) What will go wrong if optimized version will be in package? Who will not see anti-aliasing or alpha channel and where ? I mean in real life. So far I know about (outdated?) version of GIMP - my version shows everything ok.