What is an example of imagery in Romeo and Juliet?

There are several excellent examples of imagery in Shakespeare's Romeo and Juliet. Just in Act I, imagery abounds: Romeo's indictment of his unrequited love for Rosaline ("O, brawling love, O loving hate); the Prince's monologue about violence in the street ("With purple fountains issuing from your veins"); Mercutio's Queen Mab speech ("foul sluttish hairs"). Imagery is visually descriptive language which often uses figures of speech such as metaphors, similes, personification, oxymorons and others. Maybe the best example of imagery which surfaces throughout the play is the imagery involving Shakespeare's theme of light and dark. 

Romeo often compares Juliet to the brightest thing he has ever seen. In Act I, Scene 5 he uses imagery involving personification and a simile to describe Juliet across the room at Capulet's party:

O, she doth teach the torches to burn bright!
It seems she hangs upon the cheek of night
As a rich jewel in an Ethiop’s ear—

In the balcony scene, Act II, Scene 2, Romeo uses a metaphor to compare Juliet to the sun:

But soft, what light through yonder window breaks?
It is the East, and Juliet is the sun.

A little further in the same speech he again employs personification and a simile to portray the light emanating from the Juliet's beauty:

The brightness of her cheek would shame those
stars
As daylight doth a lamp

Interestingly, Shakespeare alternates his theme of light and dark. While Juliet is often described as the light and thus Romeo's cherished love, the darkness is sometimes good. After all, Romeo and Juliet's most important encounters take place in the dark during the balcony scene and the honeymoon. In Juliet's soliloquy which opens Act III, Scene 2, she uses an allusion to Greek mythology to hasten in the night when Romeo would come to her for their honeymoon:

Gallop apace, you fiery-footed steeds,
Towards Phoebus’ lodging. Such a wagoner
As Phaëton would whip you to the west
And bring in cloudy night immediately.

The images that best exemplify this juxtaposition are the birds mentioned in Act III, Scene 5. Juliet demands that it is the nightingale, symbol of the night, singing outside her window and it is not time for Romeo to leave her. She says,

It was the nightingale, and not the lark,
That pierced the fearful hollow of thine ear.
Nightly she sings on yond pomegranate tree.

The image of the nightingale represents Juliet's wish that Romeo might stay with her a bit longer before he is exiled to Mantua. The opposite image is the lark. Romeo, for once in the play, is realistic when he tells Juliet it is not the nightingale, but the lark, symbol of daylight, singing in her tree. He says,

It was the lark, the herald of the morn,
No nightingale. Look, love, what envious streaks
Do lace the severing clouds in yonder east.

Look further at Shakespeare's language and imagery is not hard to find.