Hi,
the photo shows an I-16, either type 17, type 27 or type 28th All 3 versions were equipped with 20mm cannons Shvak wing, for the precise determination would have to see the front of the engine cover, or the right side of the fuselage.
It is definitely not a Type 29 (2x 7.62 mm above the engine, 1x 12.7mm
in the lower engine cover), and no type 18 (2x 7.62 mm above the engine, and 2 x 7.62 mm) in the wings. I-16 variants to determine exactly, is a hot potato. The best way to determine just for photos, including captions are sometimes wrong. And graphics are often mislabeled.
Maybe I could help a bit? I am currently working closely with I-16 and type 17 in 1: 48 --- under construction after the original photo! best regards