That's really cool. I've seen the picture before on ebay, but always cropped really close so you never noticed the kids right next to them. I wonder which ground it's at, maybe Sutherland Oval on game day?
I first thought sutherland, but theres no way to be sure. The Parramatta photo looks like the same spot. If they played together at the start of the season it should give a clue.
Your guesses are correct... both the Cronulla-Sutherland and Parramatta pics were shot at Sutherland Oval on the Round 4 clash between the two sides on April 22 1967.
Fitz is 100% correct it is Sutherland Oval the old dressing sheds are in the top right hand corner. The flooring in those sheds had large gaps between the boards the local kids loved as small chage often fell out and under where the kids could climb under the sheds and pick it up.