It was taken on Friday the 13th, in July of 1923. (I know because the date is written on the back.)
Grandpa Teddy Schwartz and his wife, Grandma Minnie Farkas Schwartz, ran a small dairy store in the neighborhood, so relatives like Rose helped look after the twins and their older brother during the long hours when the store was open.
Fox Street and the South Bronx in general at that time were usually safe, although my Grandpa's store did get robbed once, during the Depression, on Thursday, December 16, 1937. Here's the story as published in the New York Times:
Probably Grandpa Teddy's worst ordeal came when he had to come home and explain the loss of the hard-earned $50 to Grandma Minnie!Band Robs 3 StoresThree Armed Men Get $300 in Series of Bronx RaidsThree armed men within an hour and a half held up three store-keepers in the Bronx last night and escaped with $300. About 9:30 o'clock they entered the grocery store of Theodore Schwartz at 679 Fox Street, hit him on the head with a pistol butt when he resisted and took $50. Half an hour later they went into the grocery store of Louis Lepperman at 422 Jackson Avenue and hit him with a pistol, but left quickly without taking anything when his wife screamed from a back room. In another half an hour, they forced Leonard Gaglio and his brother, Milton, liquor dealers at 1012 Morris Park Avenue, into a back room and took $250.