Faith is very personal and it means a lot to many people. Therefore it should be no surprise many incorporate images from their faith into tattoos and bodyart. The tattooing of the image of the Buddha Sakyamuni himself is generally frowned upon, although this is sometimes seen on some tattooed subjects.
The Buddha himself discouraged the use of images but over the centuries a variety of forms have entered Buddhist iconography, including the Buddha himself. Buddhist themed tattoo designs are an ever growing group as is the list of symbols that typically gets used: Bo Tree, the Buddha, a Dharma Wheel, a Kalachakra, a Lotus, a Mala, a Mandala, Om, Om Mane Padme Hum, a Stupa, a Vajra, and protective scripts written in traditional calligraphy, to name a few.