Is this a psychology dissertation? Try testing the effects of images vs. words vs. sounds on mood (the induction of FEAR ('dangers of smoking', 'drunk-driving'). COMFORT (old-fashioned toffees, grandparents), TRENDY ('hip jeans', 'alcopops', 'cars'), SEX ('perfume', 'cars').
You can test these with either one consolidated experiment, checking participants' arousal via Galvanic Skin Response, Facial Expressions.
You can also then administer an attitude questionairre. Or conduct semi-structured interviews as to what messages they found most effective. (self-report).
Your idea sounds very interesting. Good Luck.