This must be late 1960 or early 1961, since Shirley (in the middle) is 'leaning' instead of sitting up on her own. She was born September 12. That makes Bob close to 2 years old and I would be 3 in March.
I think the must be an Easter picture in our finery. Looks like a gloomy day, either way. I'm guessing it was 1964.
I think this must be about Easter, 1963.
That's Uncle Charlie behind me, and my grandma behind Shirley. I think this might have been taken in 1965. All the outdoor pictures here were taken in my grandma's back yard.