The official Japanese Pokemon website has updated their PokeDex with all of Ken Sugmori’s new artwork for Gold and Silver Pokemon. The artwork is in the same style as Pokemon he drew for Ruby and Sapphire, FireRed and LeafGreen, and Diamond and Pearl. For years the second generation Pokemon’s artwork was completely outdated in comparison to the other three generations, but now every Pokemon is drawn in the same type of style!
Note however that some Gold and Silver Pokemon’s artwork, such as Pichu and Misdreavus, was already updated when FireRed and LeafGreen came out. So, not all of the artwork is entirely new.