Is it acceptable to make a drawing that fairly closely resembles a portion of someone else's original photo, and then display that artwork? Does one have to get permission from the photographer before using for one's own purposes (which happen to be in no way monetary) the drawing inspired by the photo, or does the art belong to the maker, no matter the source? Is it enough to credit the source of inspiration? What does personal integrity dictate? And if there is a legal answer to this, what might that be?