Photo credit: "Bob (Contort Yourself)" / Flickr (click for higher res)
"Bob's" Flickr page features literally thousands of photos of street art and industrial/urban New York. It's really worth getting lost in all the many colors and textures that define the city.
More: Check out photos from the origins of the street-as-gallery movement in New York, c. 1980s.
Plus, here's a Huffington Post article on New York Street Art Tourism, which is apparently a thing.