If you want to stay in the New England area then according to U.S. News and World Report, the best photography programs are at Yale and Rhode Island School of Design. If you want to go outside of New England then the School of the Art Institute of Chicago, RIT and University of New Mexico rank vaery high on the list. This list ranks grad school programs, but the undergrad programs at these schools are just as good. I'm an NYU graduate and I HIGHLY recommend it (of course). http://grad-schools.usnews.rankings...ate-schools/top-fine-arts-schools/photography
If you are seeking a degree program, then yes you must be enrolled. If you are seeking non-degree courses (diploma program or certificate program) then some of the schools do offer continuing education classes. RISD offers a class in digital photography.