Ashcan School painter Maurice Prendergast was known for his bold, colorful depictions of leisure and play in European and American cities in the late 19th and early 20th centuries.
This view of the East River looks like a tapestry or a mosaic.
Is it showing Carl Schurz Park, on the Upper East Side? The way the land across the river looks, plus the small houses, could be Queens.
Update: David Patrick Columbia over at New York Social Diary took a look at the painting and wondering if this was Carl Schurz Park too. Here’s his investigation, with photos that seem to make the case.