The major piece of imagery to focus on is the way that the two lines which introduce the two sections of this short poem suggest the theme of what Keats is trying to convey. The poem begins with the line:
The poetry of earth is never dead
Roughly in the middle of the poem, the second section of the poem is introduced with the following line:
The poetry of earth is ceasing never
These two lines indicate the message of the poem and capture the imagery of what Keats is trying to convey. The music of nature is characterised in the image of "the poetry of earth" and the role of the grasshopper and the cricket in ensuring that, even when all of nature is quiet, that poetry still continues is highlighted and praised. For the grasshopper, even when it is so hot that the birds are hiding in "cooling trees," sings out and "has never done / With his delights." The cricket sings out earth's poetry even on winter nights "when the frost / has wrought a silence." Thus nature conspires to perpetuate the poetry of earth no matter how inhospitable the situation.