The OP seems to confuse the concept of mole with mass. The mole is a just a unitless number equal to 6.02 X 1023. In order to speak of a mass you have to multiple this number by the mass of a silver atom. In this case a gram mole of silver would weight 107.9 grams. So it is perfectly possible to speak of gram moles, kilogram moles even pound moles. Perhaps this misunderstanding leads him to believe that the amount of silver in film is not important.