Sri Krishna statue at Udupi was conscrated by Acharya Madhva, after establishing a firm foundation for his Dvaita Philosophy, travelling across Bharat twice. His clarity of thought about the Supreme Brahman as Vishnu, His supremacy over other dinities was an epoch making appraoach in 13th century.
The Salirama shila idol of Balakrishna, was dicovered by Madhva near sea shore, Malpe, Udupi. He personally brought this wonderful image of Krishna, which was earlier at Rukmini's personal garden, Dwaraka. It was lying in the sea for a long time, which only Madhva could visualise. This image is a bit unusual form of Krishna, as an 6 year old boy, standing with a post in his hand, as if to guard the cattle.
The Dhyansloka says: Bhyshmmi- Madhva kararchitam- Bhagavan Krishna worshipped eralier by Rukmini, and now by Madhva at Udupi . The image is worn out due to years of salt contact in sea, hence not clear. Moreover, due to Abhisheka each day with Milk, Honey and curds have made it corroded, otherwise it is a beautiful image of a boy smiling.
There were earlier rumours about the identity of image as Skanda, Devi and so on, which is utter lie and fantacy. It is Dandadhari Krishna, in his childhood. He has marks of Upavita, crown of a prince, and ear rings.