If you get deeper into the roots of Buddhism, you will get a hint of the Dipankara Buddha or the oldest Buddha. According to Buddhist monks and experts, Dipankara Buddha lived a million years ago and gained enlightenment much before Gautama Buddha.
Moreover, he was the one who had predicted the fact that later, a young man of the Tibetan-Burmese origin will become the next Buddha. The prediction was about Gautama Buddha, who is the most popular. However, in Chinese origin, they pay regards to all the three Buddhas- The Dipankara, The Gautama and the Maitreya.
Usually, the Dipankara Buddha stays in a sleeping posture. However, in Chinese, Tibetan, and Nepalese culture, you will be able to see the Dipankar Buddha in a standing posture. It is the same case with this Nepalese-Tibetan statue of the Tibetan Buddha.