In 2.23 the pictures folder alone is 2.2gb(the rest of graphics combined is 0.1gb), but IIRC it is all PNG so compression could drop it by a lot without loss of quality, even more if you accept some)Nope it has both part 1 and 2 with the current translation so I am not sure how mine ended up with 1.56 gb but I think i used a compressed version of part 1 and 2 from this thread then patched it so that might explain why but it isn't linked in the post anymore
Some reduction out of audio(344mb) or the main database(Game.rgss3a - 473mb) should be possible too.