Semiotics/ Trebor mint advert analysis

Position signs: the camera and the viewer
The focal point of the camera is the unicorn's muzzle, which in turn draws attention to the mint.
The point of view positions the viewer as being not quite level with the unicorn's gaze-which would be the case were the viewer stood to the side of a large horse. This has the effect of making the unicorn superior in size, which relates to the word 'discerning' from the slogan, and the fact that (despite the fact that they're not real) unicorns are fabled to be extremely rare and thus considered to be the 'elite' of horses.
Treatment signs: devices of filming and of processing
The white background might not seem to be an obvious choice against which to depict a white unicorn and a mint. However, the white emphasises the theme of purity, and adds an element of fantasy to the image. Furthermore, white is often associated with luxury items, thus the white background provides a luxury background against which the black evening glove stands out in high contrast in terms of colour- though the bejewelled, gloved hand and the word 'discerning' are both signifiers of wealth and class.
The framing of the scene means that the viewer cannot see to whom the arm belongs, but this means that the attention is not diverted from the product or the message that Trebor wish to convey. The message conveyed by the advert may be interpreted as being that Extra Strong Mints are mints of distinction- a cut above the rest.
Content Signs: Objects in the picture and their placing
Black evening gloves and diamond jewellery are featured to emphasise the quality of the mint. This image provides a strong contrast with the scene you might expect if you imagined a stable girl feeding a pony a mint- surrounded by hay and horse manure, whilst wearing practical clothes (which stereotypically might involve various shades of khaki green and an assortment of tweeds with wellington boots). Trebor are keen for the viewer to understand that Extra Strong mints are of such a high quality, that they are certainly not a mint that you would feed to a mere pony in a stable with your bare hands.
The diamond jewellery could be considered to signify wealth and success, which relates to the slogan 'sweet success'- the mint is of such quality that it in itself is a sign of success (though in reality they retail for about 50p a packet)
The pack shot of the packet of Extra Strong mints is centred at the bottom of the advert, and draws the eye in as it is the only part of the advert that makes use of the strong colours.