Some people believe that Buddhists worship idols, but this is not true. Buddhists bow or make offerings of flowers and incense in reverence to the Buddha, not to the image. When they do so they reflect on the virtues of the Buddha and are inspired to become like him. Buddha images are not necessary, but they are helpful. The most important thing is to follow the Buddha's teachings.
There are many different kinds of Buddha and Bodhisattva images that show different qualities. For example, a statue of the Buddha with his hand resting gently in his lap reminds us to develop peace within ourselves. A statue with the Buddha's right hand touching the ground shows determination.
What you think upon grows...