Dvaravati art - Buddha Image at Wat Na Phramen, Ayutthaya. Notice that the Buddha is seated in the 'European style'. The Buddha displays none of the 'classical' mudras, and His Hands are laying peacefully palms down on His Knees.

Lopburi art goes back to the 11-13th century A.D. Lopburi was a provincial capital during the Khmer empire. At times it experiences periods of independence, but its art form and Buddha images display Khmer influence.

The Chiang Saen or Lanna style (between 11th and 18th centuries A.D.) was influenced by the styles of the Khmer, Sukhothai, India, Burma and Sri Lanka.
Buddha images typically feature a lotus bud or orb shaped finial and large hair curls. The torso is plump, with a slim waist line. The face is round and smiling, with high curving highbrows, a hooked nose and mostly narrow lips.

The Kingdom of Sukhothai had important contacts with Sri Lanka. Thai monks travelled to Sri Lanka for further religious instruction, and Sri Lankan monks settled in Sukhothai. Sukhothai religious art was thus influenced by Sri Lankan art. The Buddha images of the Sukhothai era gained important disdinguishing characteristics from the images during the Khmer and Mon era.

U Thong art flourished in Central Thailand between the 12-15th century A.D. in the period when Khmer influence was diminishing or disappearing and before and during the early stages of the Ayutthaya Kingdom. As such U Thong style was influenced by previous and contemporary styles in the region.
Depending on prevailing influences and the time frame, U Thong Buddha images are often subdivided into three groups.

Buddha images of the Ayutthaya period show more different gestures than the other previoius styles. The images display the influence of Lopburi, U Thong and Sukhothai styles.
Initially the face may be more square, and a band (U Thong influence) may be present between the hairline and the forehead. Later on (Sukhothai influence) the face became more oval, with a Sukhothai type of flame on top of the ushnisha (prominent bump on the top of Buddha's head). Typical of some images are small lines carved above the upper lip and above the eyes.