This picture is acknowledged in Bruce, J.M. <i>War Planes of the First World War</i>, 1965 (one of several places it has been published over the years) as being an Imperial War Museum photograph (date 1917/18) and therefore Crown Copyright reversion applies and it is in the Public Domain
Imperial War Museum
Bruce, J.M. <i>War Planes of the First World War</i>, 1965