1. A method comprising: comparing feature information for a face included in an input image with feature information for a plurality of reference images stored in a predetermined database to determine whether the input image satisfies each of a plurality of predetermined effective conditions for photographing, the plurality of predetermined effective conditions for photographing including a lighting condition, wherein the lighting condition is satisfied upon a determination that a first reference ratio is lower than or equal to a predetermined threshold ratio; determining whether a second reference ratio is lower than or equal to a predetermined threshold ratio upon a determination that the lighting condition is not satisfied; and providing a user with a predetermined feedback for photographing guidance that corresponds to whether the predetermined effective condition for photographing is satisfied, wherein the feedback for photographing guidance includes information that an amount of light is sufficient upon a determination that the second reference ratio is lower than or equal to the predetermined threshold ratio.