自 is a nose — nostrils and bridge, drawn front-on. Chinese people point to their nose (not their chest) when saying 'me', and the script agrees: the self is the nose. Characters about breath and smell (息, 臭) all carry it.
自己 oneself, 自由 freedom ('from oneself'), 自行车 the self-going cart — a bicycle. 自然 is nature, 'that which is so of itself' — the Daoist ideal of things left to be what they are.
Point at your NOSE — that's you: SELF.
自拍 'self-shoot' is the selfie — a word Chinese built in seconds from a 3,000-year-old nose pictograph plus 'to shoot'. The nose points at itself at last.