Five-year-old Omran, unlike Alan whose body washed ashore on a beach near Bodrum in Turkey almost a year ago, survived the air strike that demolished his home in Aleppo this week.

And, equally fortunately, he was spared the life-threatening burns and other injuries that left the then nine-year-old Phan Thi Kim Phuc scarred for life after South Vietnamese planes dropped a napalm bomb on her village of Trang Bang on June 8, 1972.

All three images graphically depict the horrors of wars fought without limits or any regard for the suffering of innocent children and other non combatants.

Each was flashed around the world shortly after its creation and each has evoked a strong emotional response from all those who saw it.

Unfortunately the images, of themselves, do not have the power to change the world.

The conflict in Vietnam dragged on for another three years after Associated Press photographer Nick Ut took his moving photographs.

The Brexit vote and a rising tide of hostility towards Middle Eastern refugees in many countries across Europe is clear evidence that the reservoir of shock and sympathy created when the image of Alan Kurdi was circulated quickly dispelled.

One wonders what lasting impact, if any, this latest moment of social media outrage that is being splashed across the Twitterverse will have.

How many people will become involved with organisations such as Amnesty International to try to help?

How many will donate to charities such as Save The Children and Medecins Sans Frontieres to provide material aid to the victims of this brutal and apparently interminable war?

How many will write to the Australian government, protesting against its treatment of refugees who arrive by boat and calling for the influx of people fleeing the conflicts in Syria and elsewhere to be assisted?

Not nearly as many as one might hope.

Reacting to a tragic image on social media may help people feel as though they are expressing a useful form compassion.

It can even contribute to a sense of complacency based on the belief that, by acknowledging something, we have acted to change it.

One of Britain's greatest prime ministers, Benjamin Disraeli, observed that "history is made by those who show up".

If the horrors of war, violence, cruelty and indifference to the suffering of others are ever to be ameliorated, it will be when the wealthiest, best-educated and most fortunate members of the global population make the time and effort to "show up" in support.