It's the perfect business model. Finalpixx, the obscure paparazzo agency for which Britney Spears' boyfriend last worked, has scored a series of lucrative exclusives since he landed the troubled pop star. Now comes news that the Anglo-Afghan photographer, Adnan Ghalib, is also being paid by Spears to act as her personal assistant. Hollywood may be appalled by his mercenary nature; but the entertainment talent agencies at least must give a little grudging admiration for Ghalib's ability to make money at both ends.