“What Is a Photograph?,” the question that I.C.P. asked earlier this year, has been echoed in a slew of recent exhibitions, few as savvy, provocative, and elegant as this one. Organized by the curator Debra Singer, it includes Mariah Robertson, Michele Abeles, Lucas Blalock, Ryan Foerster, and other young artists who use photography not as a window on the world but as an expressive, process-driven tool. Many of the best works are abstract, the result of darkroom or digital manipulation, but even representational images, like the knockout Barbara Kasten piece that opens the show, redefine the medium on their own terms. Through Oct. 25.