This is one of the clearest color photos you’ll see from the 1960s. I’m guessing it was taken with Kodachrome or Ektachrome film, which was state of the art back then. (Does anyone still use photo film?)
This one’s easy to pinpoint. We are looking at a scoreboard that has 20 teams on it, and the Cubs score line has been moved to the middle, so the earliest possible year is 1962. In the seating area, we see the folding chairs that the Wrigleys used until they replaced them with permanent seats in 1965. (In 1981, when the team was sold, they put all those folding chairs, which they had stored in a sub-basement that no longer exists, out on Sheffield and sold them for $1 each.