[GasHouseGang]

It looks like Shibe Park's outfield wall.

Found this info online from an SCD article
By John McMurray

Because of its distinguishing horizontal design showing players as if they were appearing on a large, brown-bordered color television set, the 1955 Bowman baseball cards are among the most recognizable ever made. Apparently inspired in part by the 1950 Drakes baseball cards, which also employed a television-set presentation, the ’55 Bowman baseball cards represented an obvious departure from the understated styles which both Topps and Bowman generally used throughout the 1950s.

With many images of catchers about to field a pop up, Stan Lopata (No. 18) being a good representative example, and pitchers from the waist up about to begin their windups, such as No. 152 Johnny Klippstein, the 1955 Bowman cards are sometimes remembered for their consistently similar player poses, ostensibly all from photographs taken at Shibe Park in Philadelphia.

Picture of Shibe Park: