if u are using digital cam or dslr with LCD
when the object ask, " did u just snap pic of me? "
just reply back "yes" with smile and let him or her have a look of that pic, if he or she wan u to delete, just delete infront of he or she, if the object happy with the pic then keep the pic

if u are using film camera
just say no to them, cuz cant view back the pic u took, no screen.. lol