The photo is from a US source--The William Morris Agency--who appeared to be representing the sisters in the US. The height of their various media appearances in the United States was circa 1950s and 1960s; this photo appears to be from that timeframe.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.