Shiva/Parvati: This image was chosen to represent union and non-duality. Not just union between husband and wife but also union of the masculine and feminine energy within each of us.
In her Parvati form, Shiva's consort is adored by married women for a happy married life. Parvati and Shiva are doing puja (worship) before the more abstract form of their very energy - the linga/yoni. In essence they are worshipping the divinity within themselves. Both Shiva and Parvati are known by many names. These names just depict different qualities. In essence they are all the same. Parvati is Shakti. Even Shiva and Shakti (Power) are the same. There is no duality in union. All is divine.