The first photos of Hiroshima and Nagasaki from the air were published within days of the attack. The first photos of the damage from the ground were published after Americans were allowed into the cities in September 1945. These photos are the famous "rubble" ones you have seen, where all of the bodies have already been cleaned up. Reports on the medical effects of the bombs, including some of the more famous photos of injured/burned Japanese, came out in the subsequent months.

The scrutiny of Hiroshima/Nagasaki started immediately after the attacks but got much more prominent when ground-level works like John Hersey's Hiroshima came out (Hiroshima ran as a full New Yorker issue in August 1946, a year after the attacks). These portrayed the attacks from the eyes of people on the ground and helped make them less abstract.

It is hard to summarize easily the role of these attacks in the broader discourse on nuclear technology. I would take a look at Spencer Weart's Nuclear Fear: A History of Images. It is one of the better books on the development of attitudes regarding all things nuclear. On Oceania I know a lot less, but there are books like Rebecca Priestley's Mad on Radium: New Zealand in the Atomic Age and Christine Leah's Australia and the Bomb which are good places to start.