Dragon is a noble and powerful symbol of Kingship and sacredness of Divine Power (Buddhism).
Dragons in each dynasty had different shapes, from the Ly dynasty to the last feudal dynasty - Nguyen - the dragon image changed a lot due to local and regional cultural influences (Champa, China) but they all demonstrate the inherent beauty of authority and domination of a Southern empire.
The Fire Dragon painting is based on the image of the Naga dragon in the Eightfold Assembly of Buddhism, with the magic of the five elements, appearing in the form of the fire element, dominating the sky and bestowing blessings on the world.