The photograph is in a postcard format, with "The Empire Studio" (location unfortunately unknown) blind-stamped at lower right, and has the handwritten inscription, "With love, Arnold - July '16." The cap badge is, once again, a flaming grenade. Perhaps the experts could point to a regiment once more, please?
Harry Needham responds unequivocally:
Now here is one we can work with! Look at THAT spade shape, and how the bottom of the flames droop close to the grenade. Quite a coincidence, but here's another Royal Fusiliers cap badge.Nigel found some images of the cap badges for many English Regiments, in the form of cigarette cards, on the New York Public Library Digital Gallery. These display very clearly the differences to which George and Harry have referred in previous posts.
The reverse of the postcard unfortunately gives few clues as to the identity of the subject, or the studio at which the portrait was taken:
However, the stamp box design gives a clue to the publisher of the postcard stock.
CYKO is listed by Ron Playle on his web site "Real Photo Post Cards" as having operated from 1904 until the 1920s. He also shows some variation in stamp box design, which is consistent with the date inscribed, and that suggested by the uniform.