Today, the Pokédex of the official Japanese Pokémon site, which works similarly to its counterpart on the English site, updated the art of the Generation II Pokémon that were not updated for FireRed and LeafGreen. The new art now completes the transition of all 493 Pokémon to Sugimori's new art style, which was introduced in the official art from Pokémon Ruby and Sapphire, and has continued up to the present.
The Bulbawiki network uses the art from the Japanese Pokédex for the Pokémon articles on Bulbapedia. The new art will be uploaded to Bulbagarden Archives as soon as possible, while the old art will subsequently be preserved under a different file name as the Pokémon Red and Blue artwork of the Generation I Pokémon has.