Explain the imagery in the poem?

Because this poem is exquisite, readers are often
oblivious to the many images that Keats employs. Indeed, the poem is loved by many
persons who might wonder if knowledge of the images could add anything to their
appreciation. The fact remains, however, that Keats created the images as an integral
part of the poem, and therefore to understand them is one way of following the processes
of his thought and poetic art. The images throughout the poem suggest ripeness, harvest,
rest, and beauty after labor. The trees are loaded with apples; the machinery (cider
press, reaping hook) is that which is used at the time of harvest; the light is red and
mellow—rosy—and is reflected in nearby plains of cut grain; and the sounds are those of
twilight and night—not threatening but restful.