There are many people who do not consider Buddhism a religion, partly because Buddhists does not worship anyone, let alone any idols or images. We do not worship deities, gods, spirits, God, or Buddha. Even the Buddha did not claim to be god, neither do we treat him as god, but the wisest teacher who relieves our sufferings of samsara, gives us insight on life, give us the dharma that leads to bliss and joyfulness, and Wisdom.
There are Buddhist figures that appear in other religions, the most commonly known one is Guan Yin. Guan Yin is commonly worshipped by the Taoists. However there is a lot of difference between Taoism nowadays and Buddhism. Guan Yin, along with other deities like the Jade Emperor. The Jade Emperor in Taoism actually derives from Buddhism, one heavenly king we call Lord Sakra. As the Lord Sakra is not yet enlightened, we do not take refuge in him, neither do we worship him, but we pay reverence and repsect to the heavenly deity also. Other characters like Ji Gong, is also from Buddhism. However it is protrayed very differently from what it really was. Ji Gong was an enlightened saint [an Arhant]. He is being freed from Samsara and enters Nirvana after his death. He is is no longer trapped in the rebirth cycle of Samsara. However very unfortunately some people worships Ji Gong as a form of spirit-deity. This is a very deluded view. The spirit/ghost realm is one of the 3 lower realms, the Arhant who is free from samsara, how could he possibly be reborn in the lower realm?
We take refuge in the Triple Jems, which are: Buddha, Buddhadharma [truths & teachings], and the Sangha [community of monks]. In Buddhism, Guan Shir Yin Pu Sa [Avalokitesvara Bodhisattva] is a role model of the Mahabodhisattva [Da Pu Sa], someone whom we should learn from, one who seeks liberation himself and also helps liberate the other sentient beings out of great compassion.
We revere our world honoured one, Buddha Shakyamuni, and other Buddhist Bodhisattvas and Saints (Arhants) whom set an example for us on the path towards Enlightenment. We bow to them in reverence respect, also a practise of eliminating the "Ego-Form", but we do not really worship them like in other religions. Definitely Buddhists do not engage in Idol-Worshipping, which is clearly stated in the Diamond Sutra:
"If one sees me in forms,
If one seeks me in sounds,
He practices a deviant way,
And cannot see the Tathagata." - Buddha
In fact forms and statues of Buddhas are a later development of Buddhism and did not appear at the very beginning.