Everyone looks happy in the picture.
The piece is a classic rendition of Gautama right after his enlightenment.
He had been a renunciate ascetic yogin for years and so the emaciated look.
The story is that at one point he was offered some milk and because he took it and advised his fellow ascetic cohorts of its value in their work they shunned him for breaking some particular dietary vow, and soon after he vowed to sit untill he knew.