First off, it’s worth noting that after the time and effort Topps went into to get him portrayed on the right team, it was all for naught as Gaston’s Major League playing days were already done by the time this card came out.
Secondly, finding the original Topps negative which shows the interesting “half” airbrush job is worth taking a look at.
As you can see Topps basically airbrushed just enough of the image to get Gaston as a Pittsburgh Pirate player, leaving the bottom portion of the shot untouched, showing the actual Atlanta Braves uniform.
Being that Gaston played the last TWO games of the 1978 season as a Pirate instead of a Brave, for whom he played 60 games, it’s easy to see why Topps was missing an actual photo of him in the right uni.
Gaston closed out an eleven-year career in the Majors after the 1978 season, eventually becoming a manager of the Toronto Blue Jays over 12 seasons, leading them to consecutive World Series wins in 1992 and 1993.