I'd say its a 1920's photo:
A 2nd cousin of mine has a huge box full of our family photos. You see a LOT of photos from the 1920's - people had disposable income and the Kodak box camera could be had for not too much money. People took photos and developed them.
And then the 1930's came. All of the snapshots cease. There are occasional family group photos but the volume of photos dropped more than 90%
In this photo, everyone appears to have on relatively new clothes, the children look well fed - a stark contrast to a photo that might be taken in the 30's.