The man in drag is apparently Able Seaman Arthur Roach, a crew member of the H.M.S. Prince of Wales.
He poses as a milkmaid behind a wooden fence and in front of a painted background. He is wearing a rather odd hybrid fancy-dress outfit, part showgirl/courtesan (ruffles and jewelry), part little girl at the seaside (very short skirt, bucket and spade).
(Photographic postcard by H.J. Bond, 1906. From: James Gardiner Collection/Wellcome Library)