Imagery: Imagery is descriptive language that evokes sensory experience (in any or all sense modes), and is intended to make the reader feel more interested and more emotionally involved in the work by creating a mental image of the subject.

example: after apple-picking
"Magnified apples appear and disappear,
Stem end and blossom end,
And every fleck of russet showing clear.
My instep arch not only keeps the ache,
It keeps the pressure of a ladder-round.
I feel the ladder sway as the boughs bend."

In after apple picking, the speaker is done with his life's work of apple picking, whether you interpret this as an allegory for being done with his life's work is your own opinion. in either case, he uses fine tuned imagery to describe what he believes he will dream once he finally gets his sleep. He uses the sense of touch and sight to evoke an ache in ones soles, and an intimate connection with the apples. By evoking similar emotions to what he is feeling, the speaker attempts to let you see through his eyes and walk in his shoes.