>>28561151It's the initial design for Blaine. He seemed to originally be associated with the military, or perhaps he was an explorer. In the Japanese guidebook for Red and Green, his old art was used, despite the fact that his in-game sprite made use of his modern design. The book was later updated with the second picture you see here.
Other forms of media have referenced this old design. The anime used the old hair and face, but they also gave him a disguise where he wore sunglasses, a mustache just like his modern design, and a wig. Pokémon Special did something similar.