Interesting facts:  "Lithophanes are a biscuit, or unglazed white porcelain decorated with a molded or impressed design.  They were produced from about 1830 to about 1900, mostly in Germany, by the Royal Factory at Berlin and by Meissen. In England the main producers appear to have been Minton and Copeland.  Most lithophanes were plaques, ranging from miniatures to larger sizes that were framed and hung with the light (either natural or artificial) behind them.  Some were set in the bottom of tankards, where they could be seen when the vessel was emptied. The paintings reproduced were mostly of the sentimental Victorian kind."