The data connection from Pluto is very slow (~1kbit/s, I believe). Furthermore, the one-way latency is over 4 hours, and the spacecraft can’t transmit to Earth at the same time it is photographing. So to a good approximation, the encounter will take place over just a day or two of near radio silence, followed by several months of images and other data slowly dripped back. (New Horizons can’t see much once it’s gone past Pluto since everything will be dark, other than a few measurement of the atmosphere by looking at sunlight passing through it.) For excellent details and links about what you can expect to see when, look here and here. For a nice Wikipedia-level PDF, see here, and for an infinite rabbit hole of message board links, see here.
Added: New image, still well below the max resolution we will eventually see.
Added: New Horizons survived the encounter.