This is a "lithophane"; a thin translucent porcelain night light, made using a lost art from the 1800's. When lit from behind, the light shining through the different thicknesses of the carving causes a highly detailed image to appear in front, almost magically. As you see, the illuminated image is so detailed, that it has a totally photographic quality to it! In addition, the relief of the carving gives the image a 3 dimensional quality when seen in person.