Krishna is the eighth incarnation or avatar of Lord Vishnu. Krishna is famous for playing the flute. His flute playing would beguile the cow herder's daughters whom were all in love with Krishna. Krishna, besides being a hero and central figure of Bhagavad-Gita, was seen as an affirmation of life. He loved life and lived his time on this earth to the fullest. There is a cow behind him licking the underside of his foot

Only the unlearned deem myself (Vishnu) and Shiva to be distinct; he , I , and Brahma are one, assuming different names for the creation, preservation and destruction of the universe.  We, as the triune Self, pervade all creatures; the wise therefore regard all others as themselves."
~  Vishnu explains the Nature of the Trinity (trimurti ~

Vishnu is one of the principal Hindu deities, worshiped as the protector and preserver of the world and restorer of dharma (moral order).  He is known chiefly through his avatars (incarnations), particularly Rama, Krishna and Buddha.  In theory, Vishnu manifests a portion of himself anytime he is needed to fight evil, and his appearances are innumerable; but in practice, ten incarnations are most commonly recognized. 
Vishnu appears to be a prime example of how older gods and cults have been absorbed into Hinduism.  Thought to be linked with an earlier sun god, Vishnu's ten incarnations may also be examples of older gods that have been amalgamated.
Vaishnavites, one of the largest Hindu groups, are the devotees of Vishnu as Ishvara, the Supreme Being, worshiped in the forms of his manifestations or incarnations.  Because of his pervasive presence, images as the focus of worship are of great importance, as are temple architecture and carving.

The Ten Avatars of Lord Vishnu

Vishnu's preserving, restoring, and protecting powers have been manifested in the world in a series of ten earthly incarnations known as avatars.  The avatars arrive either to prevent a great evil or to affect good upon the earth.  Nine are said to have descended already: three in nonhuman form, one in hybrid form and five in human form.  The most important are Rama, fearless upholder of the law of dharma  and Krishna; youthful hero of the Bhagavad-Gita  Vishnu's final avatar is expected to arrive at a time when the earth is at the end of its present cycle, with the purpose of destroying the world and subsequently recreating it.
Matsya the Fish - Saved humanity and the sacred Veda text from the flood.
Kurma the Turtle - Helped create the world by supporting it on his back. 
Varaha the Boar - Raised the earth out of water with his tusks.
Narashima, half-man, half lion - Destroyed a tyrant demon king.
Vamana the Dwarf - Subdued king Bali, a powerful demon.
Parashurama the Brahmin - Destroyed the warrior caste.
Rama - Rescued his with Sita and killed the demon Ravana.
Krishna - told the Epic poem Bhagavad-Gita to the warrior Arjuna.
Buddha - The enlightened one.
Kalki the Horse - Yet to come to the earth.