The two exposures - 339 and 341 - were taken moments apart as the Walrus flew along the shore either north to south or south to north (can't tell which).
I went back to the uncropped images to look at wave patterns, and noticed in the full frames we have a good indicator of the direction the airplane was flying - the "thingy" in the upper left corner of the image. (I googled up photos of the Walrus, including one being craned aboard the HMS Leander (attached), and couldn't figure out what the "thingy" is.)
At any rate, image "_DSC0333" shows a wider field of view than _DSC0341. We see the same "thingy" in the upper left corner, as well as the front end of the starboard wing pontoon mid-frame on the right side of the image. From this orientation we can deduce that the observer was taking pictures out of the starboard window, and the airplane was flying south to north. However, I will hazard a guess that our Walrus crew always had the sensation they were flying backwards. . .(i.e. we'll have that spiffy Spitfire please. . )
Respectfully submitted, John