With Stanley Kishel, Crew Chief for this aircraft, and "A" Flight Chief.
Based on the number of bomb symbols painted on the nose, this photo was taken after 25 July 1943 (the aircraft's 6th mission) and before it was transferred to the 544th between 29 July and 12 August 1943.
The reverse side of the photo has enhanced areas to make some markings clearer.
Source: The Quentin Bland Collection. Additional images of this photo provided by Marc Poole and the Ken Decker Collection.