Let us remember that imagery is any verbal picture created by words that helps us to imagine the scene that is being described. The most effective examples of imagery are ones which appeal to as many of our five senses--taste, sight, sound, smell and touch--as possible. If we look at this excellent short story, there is an excellent example of imagery that comes towards the end, after they have left the boat and reached the fair:
We walked to the fair--there was the smell of popcorn, the sound of guitars. I may have danced once or twice with her, but all I really remember is her coming over to me once the music was done to explain that she would be going home in Eric Caswell's Corvette.
Note the way that the image of the fair is created through the smell of the popcorn and the sound of the music that they dance to. Although the narrator's memories of this night are not clear, he is still able to summon up elements that paint a very definite image of what it was like, and the appeal to other senses apart from sight help strengthen this image.