Most Roman sculpture, and art of all kinds, was heavily based on Greek examples, and oftentimes it can be hard to distinguish between a Roman original and a Roman copy of a Greek sculpture. However, one major distinguishing feature of Roman sculpture is in its portraiture. Roman portraits depicted their subjects in a "warts and all" manner that showed every imperfection, as it was seen to exhibit worldliness and wisdom.

A register divides the picture plane horizontally, often providing the ground line for figural decoration if it is present. Registers are used especially in relief sculpture to provide spatial order within the composition. A frame would refer to the elements that actually surround and close off the picture plane.

The Dying Gaul is a statue most likely originally cast around 200 BCE by a Greek king to commemorate his victory over the Galatians, a Celtic tribe living in modern day Turkey. The sculpture is remarkable for showing the bravery and humanity of the subject, who is marked as Galatian thanks to his haircut and necklace. The Dying Gaul that has survived is a Roman copy of the Greek original that is currently held in the Capitoline Museums in Rome.

The Dying Gaul is a statue from the third century BCE and is among the most famous pieces of Roman artwork. The statue is remarkable for its tension and lines in the prone figure, who is slouching into repose from his wounds. Additionally, the face conveys an astonishing amount of pathos and misery, while also showing a perfect form in the figure's body.

This sculpture, the Venus Braschi by Praxiteles, is a textbook example of the Classical period of Ancient Greek sculpture. The subject is calm, and has her weight shifted onto one foot, which is commonly seen in other sculptures of the same period. The sculpture has realistic, yet idealized proportions and body shape. It is also made of marble, which was not used for sculptures during the Archaic period.

The Hellenistic period consisted of a lot of movement, emotion and dynamism. As this sculpture's subject is a calm, idealized, very symmetrical female, this would not be a good representation of Hellenistic sculpture.

This sculpture is called Peplos Kore, and has been dated back to 530 BCE, during the Archaic period of Ancient Greek sculpture. The sculpture showcases one of the archetypal figures of Archaic sculpture: the standing draped woman. The subject also showcases what is known as the "Archaic smile," a bland, smiling facial expression born by nearly all Archaic Greek sculptures after 575 BCE.

This sculpture, called Laocoön and His Sons, is a clear example of late Hellenistic Greek sculpture. It is less focused on symmetry and beauty, and is more focused on the emotion and movement of the scene it is illustrating. The facial expressions and panicked and angry, as opposed to serene or neutral, as seen in Archaic and Classical sculpture. Also, this sculpture features children, which are not often found in Classical and Archaic Greek Sculpture. 

The Byzantine period was not a period of Ancient Greek sculpture.

Black-figure vases such as this one by Exekias depicting Ajax and Achilles playing dice are emblematic of Athenian ceramic production during the Greek Archaic period (c. 600–480 BCE).

Image: Ajax and Achilles Playing a Game, by Exekias (potter and painter), c. 540-530 BCE. Black-figure painting on a ceramic amphora.

Exekias [Public domain, CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons.

The Discobolus of Myron depicts a nude male discus thrower poised in the act of hurling the discus. With his head bent down, his knees bent, and his throwing arm extended behind him, the figure is frozen in a dynamic, athletic posture. Unlike later Greek art, Early Classical sculpture was concerned with portraying ideal human form, and the youthful male nude was considered the most beautiful of all the human forms.

Like many Early Classical sculptures, the Discobolus of Myron was made of bronze. While sometimes more difficult to work with than marble, this medium is generally lighter than stone and allowed for more innovative, dynamic postures.