The 178 painted panels of the Ramakien epic murals at Wat Phra Kaew are a masterwork — what you're looking at.
The Thai version of the Hindu Ramayana epic — the story of Rama, Sita, Lakshmana, and Hanuman — depicted across 178 panels spanning the full perimeter of the gallery.
The panels read clockwise starting from the north gate; Hanuman (the monkey general) and his monkey army are the most identifiable characters — white-faced, elongated figures.
Watch for the elaborate battle scenes; the demon king Ravana (green-faced, multi-armed); Hanuman's many heroics; celestial creatures in the sky sections.
Guided tours include mural explanation — worth it; alternatively, buy the official illustrated guide sold at the Palace entrance.