Note that the craft can't take pictures and send data at the same time, so it only sends back a few navigation images and only periodically, fewer now as they're doing more science as it gets closer. It also takes up to 4 or 5 hours to transmit the images (I think they're down to ~1 kbps now). The last few seem to have been posted within less than a day of the team receiving them.

You can see the transmission schedule here: http://www.planetary.org/blogs/emily-lakdawalla/2015/0624055... (images to be posted on the raw image page are in bold)