Here's why:
* Imagery uses vivid language to create a picture in the reader's mind.
* The passage uses descriptive words like "fearful," "coarse grey," "great iron," "broken shoes," and "old rag" to paint a picture of a man's appearance.
* These details evoke specific sensory experiences (sight, touch) and create a strong impression of the character.
While the passage could be considered a character sketch, imagery is the primary literary device being used to achieve the effect.