Broadly speaking, religious iconography is the artistic depiction of religious figures, often using symbolism. In Christianity, iconography features subjects such as Christ, Mary, or the saints. An icon is an image, usually painted on wood, that is to be venerated as a sacred object. Icons can also be engravings, mosaics, or embroideries. Although people who use icons in their worship would deny that they are practicing idolatry, it is difficult to see how “venerating” an object as “sacred” is different from idolatry.