This is a well known photograph, and probably the best available of 'White 42'. Because of the tail of 'White 54' fitted to this aircraft, it was naturally thought to be 'White 54'. The photo was taken at the apron of a yet to be identified airfield, with a glider transport (?) in the background. A likely location is Freeman Field.
The photograph shows many interesting details. First of all the small ammo loading hatch just behind the rear-view windows. This shows that the aircraft originally had MG 151/20 guns, and thus was one of the 40 or so first aircraft ever built. However, the wing roots appear to be those of a MK 108 canon-equiped example. In this picture the small opening just above the gun port can be seen (indicated with a ring of paint or chipped paint), that was used for boresighting of the MK 108's. The rear view windows are another indication that this a very early aircraft, since the forward frame follows that of the canopy, with a blanking piece of sheet metal covering the forward part of the transparancy. The cooling air inlet on the rear fuselage is also identified with early examples, like 'White 05' during its testing days. The tail wheel is unfaired, and the antenne behind the cockpit is missing. The small hatch at the base of the fin is missing too, and the fin tip is slightly crumpled. Lastly the pitot tube is missing.
Much can be said about the colors and markings. The side of the front fuselage is covered in a dense mottling, which is not very common. The rear fuselage has fairly large and wide-spaced mottles. Noteworthy are the two very dark mottles between the wing's trailing edge and the rocket exhaust. The fuselage Iron Cross is placed rather high. The 13. or 14. Staffel badge on the nose can be seen to be handed. The tail (which doesn't belong to this fuselage) appears to be solid painted, with a splinter division at the bottom. This is incorrect: it is very densely mottled, and the lighter area at the root is normally covered with fairings; the lighter color could be primer (RLM 02). The tail fairings are clearly missing, and one can see right through the root, showing the twin tail spars connecting to the fuselage. The code '54' is painted in a distinctive font. The wings are in a solid camouflage of dark colors, with a white Iron Cross. It is roughly aligned with the wing's trailing edge. The wing root panels are likely replacement panels, their color being close to the RLM 76 (most likely) base coat of the fuselage. Whether these wings actually belong to the 'White 42' is another question. The wheel has checkers.
Photograph from 'Wings of the Luftwaffe' by Eric Brown, scan courtesy of Hugh Rees