This is a picture of the Yak-1 dated to the summer 1941, outbreak of the Great Patriotic War.

20 iap was formed in March 1938 in Smolensk, equipped with I-16 and I-15bis planes. After its participation in Soviet-Finland war the regiment was re-armed to Yak-1 and become part of the 63 sad. At the outbreak of the GPW 20 iap become a part of the 17 sad in Kamenec-Podolskij region.
In august 1941 another independent regiment was created from this 20 iap, which had the same number – 20 iap - and become part of the 61 sad at the Briansk front. (source: http://allaces.ru/sssr/struct/p/iap20.php).
This Yak-1 has still prewar protective painting and marking. The fabric skin on the fuselage and wings is painted with AII green for uppersurfaces and AII light blue for undersurfaces while metal parts seems to be painted with A-19f gloss green and A-18f gloss light blue alkyd paints.
Red stars without black outline were on six positions – underwings, upperwings and sides of the fuselage. No red stars on the tail.

Photo of the original:

Source of the photo: http://www.airfield.narod.ru/yak/yak.html