The photo is undated. The group was initially active from 1966 to 1968. A look at this photo of Clapton and then a look at photos of him in the 1990s when the group re-formed again, and in 2005, when they also re-formed, shows the difference in his age from then to now. The musicians shown in this photo are quite young.
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.