A group of McClains, picnicking—possibly where Monteith Riverpark is now in Albany…

This is another cute photo of Uncle Bernard McClain (seated in the middle). Other identifications, according to Mom/Florence: The man in the hat with his back to the camera is Arthur McClain. The young man standing, facing him is one of the Warren twins (Ray or Roy). The little boy whose head is visible above a picnic basket (or something), just left of the car fender, is Charles Warren (who turned two in 1921). Those are all the identifications Mom provided.
I don’t think she noticed the woman in the scarf to the right of Charles. In the original photo, her head kind of blends into the pillar behind her. Solely on the basis that she is next to Charles, I’m going to guess that is Nellie Warren. But since her face is not visible, there is no way to confirm that.
On the left edge of the photo there is a seated woman who appears to be holding something (I can’t make out what). Her head is out of the frame (or mostly so). I assume this is Addie McClain, since her feet are practically against the leg of the hatted man identified as Arthur. I can’t quite work out what the white blob in front of her legs is. Possibly just a blanket. Or possibly a child in light-colored clothing (in which case it is possibly Aunt Betty—she would have been four if this was taken in 1921).
There are probably a lot of places in the area where they could have been picnicking next to pillars and cross-members such as you see behind them here. But these look a lot like the supports for the south approach to the old Steel Bridge in Albany. If that is really where they are, that area today is part of Monteith Riverpark. (The Steel Bridge was demolished in 1926, about five years after this photo.)