In looking at the scoreboard, the Cubs were at Crosley, St. Louis was at Pittsburgh, Brooklyn was at Boston, and New York was at Philadelphia.

Also, in looking at the bottom of the scoreboard, it definitely states that the next game is with Chicago and it appears that the day states "Sunday" and they are playing two games.

There are two series during the 1949 season that all of these teams are playing at the same time. All of these teams are playing on May 13, 14, and May 15, 1949. The Reds and Cubs play a doubleheader on Sunday, May 15. Also all of these teams played on August 19, 20, and 21, 1949. The Reds and Cubs play a doubleheader on Sunday, August 21.

In looking at the uniform numbers on the scoreboard, everything appears to check out with the exception of the Cubs #16. The Cubs had a #16 that season but he never caught a game according to www.baseball-almanac.com. None of the uniform numbers on the scoreboard work for any other season besides the 1949 season.

According to the clock, it is 12:40 P.M. I would assume based on all of the above, this photograph was either taken before the Saturday game on May 14, 1949 or before the Saturday game on August 20, 1949. I believe that if it were taken before the Sunday doubleheaders, it would have the next game as the Monday game and the Reds and Cubs did not finish either of these series on Monday.