The May/June issue of Family Tree Magazine, page 51, may be helpful. There are a few pictures from different decades. Your picture is most like the one for the 1890's. According to the article, sleeves were full at the shoulder and snug at the wrist. The silhouette was hourglass. Skirts were smooth at the hips. Short, frizzed bangs were common. I see that the girls and young women have fuller hairstyles which apparently was more common in the 1900's, so there is a possibility the older women were wearing earlier fashions, as someone else mentioned. Perhaps there were sisters, sisters-in-law and/or cousins in the picture, as well as a grandmother, judging from the different facial characteristics.