In the top Centre is the Buddha. In this picture he represents the union of Wisdom and Compassion, the union of Knowledge and Liberation. Emanating from him are 5 Bodhisattvas representing the 5 Buddha Families. Normally these are represented by Buddhas with the same names.
In Buddhism, a Bodhisattva is a person who makes the vow not to attain his own freedom from suffering until all other beings are freed first. They vow to be reborn in suffering existences again and again until all other beings are free.
In the Centre is Vairochana who represents all-encompassing wisdom which is the counterpart to the negative quality of Ignorance. He represents the purified Consciousness of the Buddha Family.
At the bottom left is Vajrasattva who represents Critical intelligence which is the remedy for Fear and Anger. He represents purified Form and the Vajra Family.
At the top left is Ratnasambhava who represents Equanimity or viewing all beings as equal which counteracts the negative emotion of Pride. He represents purified Feeling and the Ratna Family.
At the top right is Amitabha who represents Discrimination which counteracts the negative emotion of Lust. He represents purified Perception. This is the Padma Family.
At the bottom right is Amogasiddhi who represents Skillful Means which counteracts the negative quality of Envy. He represents purified Action. This is the Karma Family.
Through the practice of meditation we gain calmness and clarity by eliminating Agitation and dullness which are caused by these negative emotions and thereby develop the Wisdoms and Purifications reflected in this picture. I hope this helps others understand better some of the Buddhist imagery.