My father said this tintype was taken about 1870. He wasn't always accurate in assigning dates to photos, but internal evidence also suggests 1870 as the date. My great-grandfather, Louis Windmuller, moved into this house in 1867. As I've written before, the family had been living on Dean Street in Brooklyn, but moved to Queens at least partly to see whether the country air would improve the health of his second child, Bertha, born in 1866.
The tintype was therefore made no earlier than 1867. Tintypes were supplanted by silver gelatin prints in 1880 so that's (probably) the latest it could have been made. The plantings around the house — which look newly added — suggest an earlier rather than a later date. So does the youthful appearance of Annie, seated on the porch, who was born in 1836 and was thus 34 in 1870.
From the clothes of Annie and the two servants you can tell it's a warm day. The upstairs windows may have been shuttered against the heat, but then you'd expect the downstairs windows to be open, which they're not. Since the downstairs ones are closed with shades mostly drawn, this tintype could be a record of the reopening of the house for the summer season. (The family spent the colder months in an apartment in Manhattan.) The broom in the hands of the woman I take to be the housekeeper might be intended to signify that the house is being prepared for re-occupancy, but it's hard to say; it might be just another late spring day. The lawn has recently been cut. There are flowers growing in large ornamental urns. A trellis has vines in leaf growing up it. It's odd that there are no porch railings nor any chairs, couches, or swings, just one bench.
Annie has something on her lap, maybe a shawl and jacket or other garments? I can't tell. Here's a detail view of her.
The maid standing next to the housekeeper looks small enough to be a child.
You can tell that the ground floor ceilings are high, maybe 18 feet judging by the housekeeper's height. The chimneys indicate that house did not have central heating, as you'd expect. The site seems to be gently sloped and, indeed, the family called the place Hillside Manor.
 The change of scene didn't help Bertha who died soon after they moved. See my earlier posts: an obituary and 19 w. 46th St..
 Residents of Queens were then dependent on ferry service to cross the East River and that service became unreliable in the cold months. I've previously written about the skinny building at 19 West 46th St. in which the family spent most winters. See 19 w. 46th St. and 19 w. 46th, again.
 Quite a few news clippings give Hillside Manor as the name of the estate. For example this one on the celebration of Louis and Annie's Golden Wedding Anniversary: