A week ago today a picture of a drowned Syrian toddler took over the media. How can it be assured impact?

The photo of 3-year-old Aylan Kurdi, who died together with his mother and brother en route from Syria to Turkey, depicted a chubby-legged toddler stilled by death. He lay sprawled on the sand as if asleep, his head partly submerged in water. Behind him the sea bore no sign of the family members it claimed with him.

Unlike most other photos of the ongoing refugee crisis in the Middle East and Europe, the photo came with an identity. The child had a name. A family. A heartbreaking tale of stillborn efforts to transport him and his family to an aunt in Canada.

This detail matters because most news images can't hold a whole news event in their embrace. They do not offer much about causation or context. They depict a small sliver of action more complicated than what's shown. They target dramatic moments crafted to grab attention in hopes we will not look away.

Images need help on their way to impact.

And yet, most news pictures, especially of crisis, are anonymous. They bear captions that provide only the barest information of what the public sees and credits that reveal little about who took the image and under which circumstances. They are presented in ways that keep the relationship between the photo and its adjoining news story unclear.

The picture of Aylan Kurdi offers a hint of promising change. Its accompanying detail has already helped shore multiple short-term responses. The photo is being widely displayed in the media as an emblem of the crisis. Governments are softening border restrictions and reframing immigration policies. Charities and human-rights organizations are reporting a surge in donations.

But a picture can't bring about change on its own.

The photo of Aylan Kurdi and its accompanying detail surfaced just when the public and its various sectors — officials, politicians, news executives, nongovernmental organizations, and everyday individuals — have become more open to giving the refugee crisis a platform.

Coverage has been ongoing for some time. Spurred by four years of Syrian conflict, months of stunning political inaction and the deaths of approximately 250,000 people, including children, the stories of the refugee crisis have been unrelenting. More than 2,500 people died this year alone trying to cross the Mediterranean to Europe — by drowning, crushing, and suffocation. Most were not photographed, and when they were, their pictures typically had no names or identities.

Aylan Kurdi's photo is different. It has gone viral at a time in which people are more willing to engage with what it depicts. Details foster their engagement.

We've seen this pattern before. The widely acclaimed 1972 image of Kim Phuc, the napalmed girl of the Vietnam war, followed earlier, largely anonymous, pictures of other wartime activity: an immolating monk, a Vietcong officer, a village massacre. Many of those pictures had no names or identities.

By the time the picture of Kim Phuc was taken, it landed among long-growing public sentiments against the war. By 1972, the public was ready to take action that it had resisted for much of the previous decade. No wonder, then, that the girl was given an identity and her recovery tracked over the following years.

Though others in the photo died largely in anonymity, the textured story of Kim Phuc helped carry the photo to impact. She became a goodwill ambassador and the target of documentary movies, magazine profiles, and commemorative platforms.

Pictures are given identities in the news when the public is ready for them.

How can the picture of Aylan Kurdi continue to have impact? The detail so far provided needs an afterlife. Other pictures with names, stories, and particulars need to follow. Action on behalf of the refugees needs to continue.

These developments are not certain. Already, we are seeing a return to the old normal. News outlets have resumed showing unnamed "migrants wait" behind fences, nameless "refugees crush" aboard buses, unidentified "families jam" highways. In the short interval of a week, hordes of anonymous individuals again crowd coverage of the refugee crisis.

Anonymity in photos needs to become the exception rather than the rule. If we have learned anything from the picture of Aylan Kurdi, it might be that.

Barbie Zelizer is the Raymond Williams professor of communication at the University of Pennsylvania's Annenberg School for Communication and author of "About To Die: How News Images Move the Public."  bzelizer@asc.upenn.edu  @bzelizer