Amitabha Buddha, the Buddha of Boundless Light, is a Buddha described in the Mahayana school of Buddhism. This is the Buddha of the Pure Land sect, which is a version of Buddhism practiced mostly in East Asia. According to this sect, the Amitabha Buddha glows with the added divinity of having been a bodhisattva through many of his past lives, named Dharmakara. The Pure Land sect of Buddhism started off in India, Afghanistan and Pakistan, slowly spreading later to Central Asia, China, Vietnam, Korea and Japan. In the highest Yoga Tantra of the Tibetan Vajrayana, Amitabha is regarded as one of the Five Dhyani Buddhas.
Features-wise, one cannot make out too much of a difference between the Amitabha Buddha and Sakyamuni or Gautama Buddha. Both the Buddhas possess the same qualities. The only difference is in the mudras (hand gesture). The Amitabha Buddha is seen holding the usual meditation mudra of touching the tip of the thumb to the index finger, while Sakyamuni points his right hand downwards, towards the right leg, his palm facing inwards.