>>12850813The third Pokemon game has always had different sprites, we're talking about the first two that are released and how they're only different in silver and gold.
Gen 1 was originally Red/Green in Japan with Blue being the the third improved game. Yellow was a gimmick for fans of the anime. In the US, we used the improved graphics of Blue for the initial Red/Blue release and Yellow became our third new and improved game as well as a promotion for the anime.