I have not found any information on the actual photograph yet, but I found it helpful to learn about the evacuation from Saigon in general.
In April 1975, President Ford asked Congress to use US military forces for the evacuation from South Vietnam. These military forces would be used to protect both South Vietnamese and Americans during the evacuation. The evacuation seemed necessary as an attack by the North Vietnamese was predicted from the many Communist divisions that were moving and since North Vietnamese had violated the Paris agreements of 1973 by increasing their forces in South Vietnam. Therefore, President Ford decided that the Americans left in Saigon should be extracted. In addition to these Americans (numbered at about 6,000), President Ford also was trying to find a way to protect and withdraw tens of thousands of South Vietnamese ‘“whose lives… [were] in grave peril” because of their association with the US.’
150,000 to 200,000 South Vietnamese (not necessarily those closely associated with the US) were in danger of Communist attacks and their evacuation was also considered by US administration; however, President Ford’s request for the use of US troops to protect the evacuation was ruled out to prevent a commitment of the US and because of the fear of returning to a costly war just as it was ending. In addition, Ford’s large request for hundreds of millions of dollars to be sent as emergency military funds was refused. The idea of a large scale evacuation was also dismissed because it would cause Saigon to collapse and other issues would be finding out who is eligible and how they would be protected by US Marines. Diplomatic measures were also being taken to allow a safe evacuation such as the attempt to get a cease-fire.
Evidently smaller evacuations were taking place at this time. The International Commission for Control and Supervision in Saigon evacuated most of their staff and 257 children from the American supported An Lac Orphanage were sent to the US.
This information was found from multiple articles in the Milwaukee Journal.
It appears that a threat from the North Vietnamese was approaching, but it had not completely formed yet. The increase and movement of North Vietnamese forces were, however, enough to cause Ford to plead Congress for a mass exodus from Saigon. The evacuation of the 6,000 Americans seemed like an obvious event, but the removal of South Vietnamese seemed to not be as favorable as it contained more complications. As I continue to research, I will find out if/how many US troops were used during the evacuation and how many South Vietnamese escaped.