Although one can appreciate the beauty of an object and the degree of craftsmanship involved without knowing what it represents, it is fulfilling to know what you are looking at. The following information, gathered while studying ancient Tibetan art and, by extension, ancient Buddhist art of the Himalayas, may be of some use, although it is neither comprehensive nor authoritative…
Tibetan Buddhist art is particularly rich and complex and studying its iconography seems a never-ending task as many characters can be represented in several ways to express different qualities or aspects of spirituality.
Apart from buddhas (beings who have attained perfection and reached a higher world), bodhisattvas (beings who have reached perfection but who have chosen to linger in this world to help humans overcome their suffering and progress towards a higher realm), their consorts and their attendants, there is an array of wrathful gods (who are often protectors), historical figures such as famous lamas and mahasiddhas (tantric adepts), kings, religious teachers and philosophers, unidentified lamas, and a few mythical creatures and animals. Obviously, most characters already existed in the Indian Buddhist pantheon but some are specifically Tibetan (the imported religion was integrated to the existing Bön religion), while others are mainly seen in Tibet and Mongolia or in Tibet and Nepal.
Tibetan paintings alone would take a lifetime to be studied in details as there are so many of them and they are so full of symbols and hidden meanings. There is an extensive range of tangkas and other Tibetan pictorial arts (murals, textiles, tsakali cards) on http://www.himalayanart.org with very useful explanations. See also Tibetan murals in Lo (now known as Mustang) on : http://dl.lib.brown.edu/BuddhistTempleArt
Ancient Buddhist Tibetan sculptures are also plentiful, especially in the form of statues. They range roughly from the 8th to the 18th century and can measure from a few centimetres (for a portable shrine) to several meters high (to sit or stand in a temple). They are usually made of copper alloy, brass or bronze, but sometimes silver, wood or ivory and even copper repoussé, stone or clay. Styles vary enormously from one century to the other, from one region to the other, from one school of artists to the other, and it is sometimes impossible to tell whether a particular sculpture was made by a foreign artist working in Tibet or by a Tibetan artist influenced by a foreign style. The composition of the alloy, the technique used, the type of inlay (turquoise, lapis lazuli and/or coral) if any, the finish at the back of the piece, in conjunction with the character that it represents, help determine whether a statue was made in Tibet and/or by a Tibetan artist. The facial features, the design of the crown, the jewellery, the attributes, the lotus base, the overall shape and proportions of the head and body, point to a given style corresponding to a given school of artists (Kashmiri, Nepalese, Indian, Central Tibetan, West Tibetan etc.) at a given period, but it is not unusual to find metal statues with mixed features. The presence of lapis lazuli powder (or indigo) in the hair and cold gold on the face indicates that the statue was worshipped in Tibet but not necessarily that it was made there. Some styles went through a revival several centuries later, but the more modern pieces (16th-18th century) often lack the details, smooth contours and sobriety of the older ones, not to mention the beauty and harmony of them.
Some of the finest Buddhist sculptures were made in the Kashmir region between the 5th and 12th century (after which buddhist institutions fled to Tibet and Nepal to avoid Muslim armies and brought their skilled craftsmen with them). Usually made of ungilt copper alloy, brass or bronze (more rarely silver, stone, or ivory) they have distinctive features that vary slightly according to the historical period, the region and the character that is depicted. The presence of a square pedestal, throne or cushion, a specific type of lotus base or halo, the folds of the clothes, a very developed chest and thin waist with well marked abdomen muscles and navel, semi-closed silver-inlaid eyes, a prominent silver-inlaid or stone-inlaid urna (the circle in the middle of the forehead), or no urna at all, a beaked nose, a semi-rigid pose, the shape of the crown and the jewellery, are all details that help identify a sculpture made by a Kashmiri artist in or outside Kashmir. They usually represent buddhas, bodhisattvas or the goddess Tara. Triads or groups of 5 or more standing deities with peaked halos behind them are not unusual. Some statues bear an inscription with the date on their base.
The former Tibetan kingdom of Ladakh, now part of Jammu and Kashmir in Northern India, deserves a mention of its own for its gigantic statue of bodhisattva Maitreya carved in the rock (8th century circa), its well preserved murals (possibly the only Kashmiri paintings in situ), and the large wooden, clay or metal statues in some of its monasteries (see the Huntington Archive and Himalayan Art Resources links on the left sidebar).
Apart from the murals mentioned above, some Gilgit manuscripts (now in an Indian museum) were illustrated with Kashmiri paintings. And that’s all (for the time being). Scholars are not sure whether Kashmiri paintings did not survive or whether Kashmiri artists did not normally paint, something which would be rather odd…
If sobriety defines early Buddhist Nepalese sculptures from the Licchavi period (5th to 9th century) and, to a certain extent, the Transitional period (9th to 12th century), the Malla period, divided into early Malla (13th-15th century) and late Malla (16th-18th century) is one of splendour, with lavish gilding and stone inlay (turquoise and transparent gemstones such as crystal, ruby, carnelian etc.), very ornate crowns and jewellery, large lotus flowers, big circular earrings, wide belts/sashes, flowing garments often decorated with vajra (diamond thunderbolt) motifs, extremely harmonious body shape and proportions, with thin waists and long limbs, radiant faces with large semi-closed almond-shape eyes. The urna, if any, can be round, tear-shaped, square or oblong. The majority of Nepalese sculptures are made of copper, the others are made of copper alloy or wood (usually painted in bright colours), sometimes stone or ivory. Most statues represent a buddha, a bodhisattva or the goddess Tara. Two special bodhisattvas often found among Nepalese work are the beautiful and enigmatic Phagpa Lokeshvara (see the link to Ian Alsop’s enlightening article in the left sidebar) and the unmistakable Amoghapasha Lokeshvara with six or eight arms. The Nepalese pantheon also includes a few wrathful gods and some mythical creatures such as Garuda birds and the demon Kirtimukha, both of Hindu origin. Malla sculptures are the work of Newar artists from the Kathmandu valley.
IV. The Khasa Malla kingdom
Made in a variety of metals and finishes – gilt copper or copper alloy, with or without stone inlay, plain silver or parcel-gilt silver on a gilt copper alloy base – statues from the Khasa Malla kingdom (Western Nepal/Western Tibet, 12th-14th century, and unrelated to the previous Mallas) usually have graceful Nepalese facial features, very round shoulders and short sturdy limbs, a rigid, almost doll-like pose, very curly mandorlas (the separate piece at the back), elaborate crowns, big earrings, a tall meringue-like lotus base with decorations on the lower part, and red pigment on the base and the mandorla.
V. Swat Valley
Spreading over Pakistan and Afghanistan, the Swat Valley was home to some of the most elegant Buddhist sculptures. Produced between the 6th and 11th century, they were made of brass, copper alloy or dark bronze (sometimes silver) and usually depict buddhas, bodhisattvas or the goddess Tara, sometimes with attendants. They have large silver-inlaid eyes (and urnas if any) and copper-inlaid lips, and stand or sit on a single or double lotus base, or on a square base imitating a rocky formation, or on a square cushion with big tassels sticking out on each side and placed on a square throne supported by animals (usually lions but sometimes elephants or horses). Ornaments are few and simple, lotus flowers are large, the hair is often tied up in the shape of a fan on top of the head, crowns are discrete, dhotis (loincloths) are incised to imitate the folds of the cloth. Bodies are usually harmonious with thin waists and smooth chests, arms tend to be long and ending with large hands while legs are fairly short and sometimes chubby. Poses are somewhat rigid yet majestic.
VI. Ancient kingdom of Gilgit
The most splendidly crafted Buddhist sculptures of the Himalayas come from the ancient kingdom of Gilgit, now in Pakistan. Produced between the 7th and the 8th century approximately, they are usually made of brass, gilt or ungilt, often inlaid with silver, copper and even niello (a black metal mixture). The figures sometimes sit on a cushion decorated with an intricate rosette pattern made of copper and silver inlay imitating the real cushions of the time. The Gilgit style is defined through the shape of the thrones, often with attendants and/or donors sticking out on the sides, the shape of the lions supporting the throne, the big lotuses under the feet of the characters, the folds of the dhotis, the long hair ribbons, the big silver-inlaid eyes and urnas, the eyebrows, in conjunction with the Kashmiri facial features, the stiff crowns, the round lotus flowers in the ribbons, garlands, and earrings which are also seen in Ladakh, Western Tibet and Himachal Pradesh. Most pieces are particularly well-preserved, some of them bear an inscription at the base with a date (late 7th to early 8th century).
VII. Himachal Pradesh
In the 10th century, a delegate of the Tibetan king commissioned Kashmiri artists to decorate new monasteries built in the then Tibetan kingdom of Himachal Pradesh. A few of these monasteries have survived and provide us with some precious information. Their numerous wall paintings and sculptures represent buddhas, bodhisattvas, female deities, wrathful gods etc. Some of the sculptures have the same facial features and the same crowns and round lotus flowers in ribbons, earrings and garlands as the remarkable 7th to 8th century metal statues of Gilgit. In Chamba, there is a large sculpture of bodhisattva Maitreya carved in the rock, of similar style and with similar accessories, said to be 8th century. The Himachal Pradesh Buddhist metal statues found in museums and private collections are made of brass, bronze and date mainly from the 10th-11th century. They have Kashmiri facial features, with silver-inlaid eyes. The female deities have sand-glass shaped bodies and all wear similar accessories, including a very big ear ornament on one or both sides. The statues stand or sit on a small cushion resting on a single-lotus base supported by a square pedestal or throne. Most Mandorlas are made of a circular piece topped with a tear-shaped halo. Others are made of two columns supporting a horizontal bar topped with a peaked halo decorated with an enormous lotus flower and a finial, in the fashion of 11th-12th century Himachal Pradesh Hindu statues. Among the few earlier works, there is an exquisite brass bodhisattva (Ashmolean Museum, Oxford), thought to be 7th century, with an interesting mixture of Gilgit, Swat Valley and Indian features.
A 10th-11th century wooden statue of Tara, with an elongated mandorla topped with a finial in the North-East Indian Pala style, can be seen at the Metropolitan Museum of Art (New York).