The scene of Danny photographing an execution is based an actual incident in which Chicago-based crime photographer Tom Howard (who was the grandfather of George Wendt surreptitiously snapped the famous photo of convicted murderess Ruth Snyder's January 12, 1928 execution in the electric chair at Sing Sing for the New York Daily News.
James Cagney's fast rise to Hollywood stardom began just three years before Picture Snatcher (1933) came out in 1933. This was the 13th film he made since his first one, Sinners' Holiday (1930). Even for that first film, he was paid handsomely. His salary was $500 per week for three weeks of shooting. His $1,500 for three weeks work on his very first film was more than most Americans earned in a year. The median individual income in 1930 was $1,368.
When Pat expresses skepticism, Danny replies, "Vass you dere, Sharlie?" This was the catch phrase used by the comedian Jack Pearl, who used a comic German accent, in this situation.
The Jewish tailor tells Danny that his new suit will make him "the best-dressed goniff in America." "Goniff" is the Yiddish word for "thief," as James Cagney, a New Yorker who spoke Yiddish, would have known.
Danny Kean gets released from Sing Sing Prison at Ossining, NY. Although it isn't used in this film, the phrase, "Up the river," was coined in the 1890s in reference to Sing Sing. When criminals in New York were sentenced there, they traveled 30 miles up the Hudson River to the penitentiary at Ossining. In the early 20th century, the phrase came to refer to being sentenced to jail or prison anywhere in the U.S.