Circa 1906 photo of Vassar girls at the Mill. From at least prior to 1933, if not much earlier. From the Vassar College archives.
Historic_vassar_girls
Cider Mill Friends
Preserving and Restoring the Kimlin Cider Mill
Cider Mill Friends 
I’m an experienced costume historian, and based on the clothing, this photograph is likely to date to 1914.