I doubt very much if it's the same person, as the facial features are so different. But, they could possibly be in the same regiment, as uniforms varied , depending on what they were doing at the time.
Battle dress, evening dress and ceremonial dress, and sometimes a more casual type dress code.
I would think these were a good few years before WW1. Because, in general, Khaki was pretty much standard across the Armed services by then, for general combat.
I'd hazard a guess of between 1890 & 1910.
Steve.
