About 1915.
Collection of A. Taylor
Photographer/publisher: H. Jenkins, 2, Pier Terrace, Lowestoft
For Harry,
From Your Sincere,
Chum Will
Mrs. Slater
142 Fullbourne Rd.
Forest Rd.
E 17 Walthamstow
Essex
Dr. (or Dvr) W. H. Slater 292845
Caption: No Caption
It's possible that the number after the W. H. Slater name is a the service number.