From smiling family man with a common touch to hardened military leader ready for all-out war: North Korea's propaganda machine has given leader Kim Jong-Un a visual makeover in the past month.

The rapid escalation in Pyongyang's shrill, bellicose rhetoric in recent weeks has been matched by an equally swift shift of focus in the content of the images being disseminated by the state media.

As the North's language has become ever more threatening, so the accompanying photographs have become discernibly more aggressive, both in general and in their particular portrayal of the young Kim Jong-Un.

Immediately after Kim took power in North Korea following the death of his father Kim Jong-Il in December 2011, there was a flurry of military-themed pictures, often showing Kim with senior army officers.

The obvious message was one of consistency -- a new supreme commander who had the loyalty of the armed forces and intended to continue the "military first" policy that was his father's main legacy.

"In the company of the most senior military men, the young Kim presumably gained a measure of military credibility without even having served in the army," said Katy Oh of the Institute for Defence Analyses in Alexandria, Virginia.

But by mid-2012, the tone had changed. The military-linked photos were still there, but there were fewer of them and more of Kim cutting a smiling, benign, parental figure.

As well as the "on-the-spot-guidance" photo-ops of Kim's visits to factories and schools -- a propaganda staple stretching back to Kim's grandfather and the North's founding leader Kim Il-Sung -- there were more intimate portraits.

More extrovert and clearly more comfortable being seen and speaking in public that Kim Jong-Il, the new leader was shown enjoying himself and even taking a thrill ride at an amusement park.

And increasingly there was his wife, a stylish, attractive woman who lent a refreshing touch of modernity and glamour to her husband and became something of a foreign media celebrity in her own right.

North Koreans are used to the dual image, which can otherwise seem contradictory, of their leaders being shown both as commanding military fighters, and comforting, almost maternal figures.

In his book "The Cleanest Race," B.R. Myers, an expert on North Korean propaganda, argues that North Korea has a race-based ideology that paints Koreans as more innocent and morally virtuous than foreigners, but not physically superior, thus requiring "guidance and protection" from a leader.

Towards the end of 2012 and following the North's long-range rocket launch in December, the volume of military-themed pictures first increased and then dominated after the North conducted its third nuclear test in February.

Suddenly Kim was everywhere, visiting military units on outlying frontline islands, perched on the prow of an unstable-looking open-topped boat, impervious to the wind and rain.

Photos had him in artillery pillboxes, surveying enemy positions on South-occupied islands through binoculars, always pointing and gesticulating like a conductor leading an orchestra of military officers.

When the North threatened the United States with nuclear attack, Kim was pictured at his desk in a war room, surrounded by top-ranking officers, with a map in the background showing projected missile strikes on US targets.

"The change really came after the nuclear test and the imagery quickly became menacing," said Byeon Yeong-Wook, a photographer at the Dong-A Ilbo newspaper who has monitored and edited pictures from the North's state media for years.

"We might find some of the images exaggerated or even ridiculous, but the domestic audience in North Korea would connect immediately with the portrayal of a strong and brave leader," Byeon said.

Some photos showed Kim himself with a handgun or rifle, while in others he monitored rifle training and artillery drills.

When Kim is absent, the pictures can be graphically violent.

One recent batch of photos released by the official Korean Central News Agency -- video footage was also made available -- showed trained army attack dogs going for the throat of a mannequin with the face of South Korean Defence Minister Kim Kwan-Jin.