How we cite our quotes: (line numbers)
Quote #1
Two vast and trunkless legs of stone
Stand in the desert. Near them on the sand, half-sunk
A shatter'd visage lies (2-4)
These lines describe a very strange image; just imagine two legs in the middle of the desert, with a head partly submerged nearby. When we imagine a desert, we often imagine a really hot place with lots of sand that is, appropriately, deserted. The "culture" that has produced the "art" has disappeared or, better yet, has sunk beneath the sand, just like the statue's head. The partially-shrunken head is a symbol of a vanishing, "antique" culture. And yet part of the statue is still "standing." It's hard to account for this, but it could be because its "colossal" dimensions make it hard to destroy, or because art somehow finds a way to persist.
Quote #2
...whose frown
And wrinkled lip and sneer of cold command
tell that its sculptor well those passions read
Which yet survive, stamp'd on these lifeless things,
The hand that mock'd them and the heart that fed (4-7)
These lines suggest that good art has the ability to embody and preserve passions over several thousand years; the statue is like a piece of fossilized amber, but instead of a prehistoric fly, what remains are Ozymandias's passions, kept neatly encased for later viewers. The preservation of the passions contrasts with the dilapidated state of the statue. Even though the statue is dead, it still possesses a strange life-preserving power; this is a bizarre state of affairs indeed. It suggests that art is not useless decoration, but can in fact play an important documentary role.