Rick Griffin was one of San Francisco’s Big Five psychedelic poster artists. He grew up in Los Angeles, steeped in surf culture and moved up to San Francisco at the end of 1966 with the goal of becoming a poster artist. He caught the attention of The Family Dog promoter Chet Helms who hired him in early 1967 to start doing posters for the shows at the Avalon Ballroom. This poster from March 1967 shows off Griffins early style which tended toward Wild West themes and “Wanted” poster lettering.
All of the poster artists “borrowed” images from the past and popped them into the psychedelic context of their posters and here Griffin has found the image in a book about old Imperial India. These three were actually “Soldiers of the Maharaja of Kashmir,” and the photo is said to date to the 1860s or 70s.