Imagery is an author's use of the five senses, so that the reader will be better able to visualize the words and actions about which the author is writing. The reader is able to get a mental picture, "hear" what is happening, or use one of the other senses. Below are some examples of the different types of imagery.
Visual imagery (see): The sun shone brightly, casting a yellow shadow over the field.
Auditory imagery (hear): An ear splitting scream rang out into the night.
Olfactory imagery (smell): A stench like rotten eggs filled my nostrils when I walked into the room.
Tactile imagery (touch): When she slipped on the rock, she felt the prickly spines of a cactus against her leg.
Gustatory imagery (taste): He puckered his lips as he sucked the juice from a lemon.
Authors often use figures of speech such as metaphors, similes, personification, etc. to enhance the imagery in their works.