Stewart, who died this past Saturday at the age of 73, was one of the five players the Reds sent to Houston in the Joe Morgan robbery, er, trade. This is his "Astros" picture in the Batters Pack:
It's fairly obviously an airbrush job as not only is the hat imperfect, but the Astros didn't wear plain, blue road uniforms like the one seen in the picture…the 1971 Reds wore that uniform. (Astro roadies of this era were off-white, with the same red/white/black collar-striping seen on their home kits.)
Here are actual pics of Stewart as a 'Stro, from Spring Training of (presumably) 1972:
Rest easy, Jimmy.