The Supreme Lord often incarnates on the holy soil of India. But, Lord Swaminarayan is the first ever incarnation who established his own Mandirs and established deities that are equal to his form. Lord Swaminarayan followed Vishishtadwait (Neo-Qualified non-dualism) founded by Ramanujacharya. According to it, He established Laxminarayan dev. Moreover, following the the Vaishnavism, established by Vallabhacharya Mahaprabhu, He also established different forms of Shree RadhaKrishna known as Gopinathji Maharaj, Radharamandev, Madanmohanji Maharaj etc. He also established Shree NarNarayandev, the divine emperor of these Bharatkhand in 2 Mandirs. He also established the idols of Ranchhodrai, Suryanarayan, BaldevRevtiji, The 10 incarnations, Sidhdheshwar Mahadev, Ganapatiji and Hanumanji. By establishing all these Deities, he shown equal correspondence towards it.
The historic messure taken by Lord Swaminarayan was that He established his own form in Vartal, known as Lord Harikrishna ! We can observe by this that He might be devoted by Thousands of people, as Supreme God.
Normally, the idols were made of two types. (1) Wooden (2) Sandstone. The wooden idols were normally of Shree Ghanashyam Maharaj. The idol of Shree Gopinathji Majaraj is made inch by inch as of Lord Swaminarayan’s body, it’s accurate.
The idols established with Vedic rituals by Lord Swaminarayan are still miraculous, till date and also fulfils one’s wish, who worships them with pure heart and devotion.