As you can see these are an ancient Egyptian painting of the eye of Horus. The falcon headed god of the sun, war and protection. The other is Anubis guardian of the underworld. They are rather large in size the Sculpture of Anubis being a few feet and the painting more wide than it is tall so not too big I'd assume. The posture of Anubis is amazing. The scepter and the gesture of his face feel like he is saying don't mess with me. As for the painting of the eye of Horus the eye is representative of the all seing eye of god which is interesting because there is also a serpent which in Christianity is a contradiction. It was a good sense of calm easy peace knowing that Horus was watching.
These are examples of Greek art. The top one being a bronze sculpture of Perseus holding the head of Medusa. This statue is also presumably a few feet tall. Medusa represents corruption and Perseus the end of said corruption. Wicked ways beacuse as we know Medusa was going around turning people into stone with her look. Notice how Perseus has his eyes closed and a look of consternation on his face. The bottom one is of a greek vase painting. It is not big the general size of a vase for that day so a bit bigger than the ones we have now. It is a warrior taking out a centaur. The warrior has fierce eys. It is apparent that the centaur is suffering. As you can see with these artworks the Greek was more about Ferocity showing no mercy it is apparent the centaur is in pain, where as with the Egyptian it was more about holding and attaining power. Do anything to offset that and they could be pretty mean too.
The Coloseum was a great feat of architecture where sporting events would take place. Some games could last over one hundred days. It is made of stone. It symbolizes the center of their town. Thousands of years ago people would walk by with baskets from the market. As was stated the Romans were among the first to legalize Christianity. The size is rather grand I don't have an exact or even estimate for that matter.. It doesn't really have a gesture. It however has a feeling of majesty.
This is a mosaic of the Roman hunt with Alexander The Great and and General Krateros. It is from the fourth century BC. The size is not much bigger than a tapestry. All three figures have different gesture the lion might even be a bit timid or afraid. Although just about always lions are used to represent power. Alexander and Krateros have death in their eyes. Until this time nature was to be feared as well as glorified. It was a right of passage and a skill. The Romans were more spiritual than the Greeks and more akin to the Egyptians.
This example of artwork by Ed Unitsky is unified by having contrasting colors that complement each other. You see the green, red, blue but then there is also dark and light. It all looks like it belongs to one singular world or idea/concept. 
This art by Lydia Burris is balanced asymmetrically as you can see the faces go from left to right. It also goes by the weight of color and form. The face in the upper right grabs much more attention than the one on the lower left or even the one adjacent to it. They are roughly of the same size but the smaller ones definitely balance out with the larger ones. The reflection and not being able to see all of it also importantly balances out this work of art.
Scale can change the meaning of artwork such as this one made with the help of WETA in a number of ways including making something in this case gollum much more important than he is. Though he is very important to New Zealand and Tolkien fans who read or watched The Hobbit and Lord Of The Rings Trilogies. This is a large scale sculpture in the Wellington National Airport in New Zealand. They are aware that is a good part of the reason why anyone goes there which is why they have these in the terminal. In the movie for example he takes a fish out of the water and eats it. With this sculpture you see that same scene play out over your head on a much grander scale. It has mind you much more minute detail. You feel really small in comparison.
