The premise of the poem is a striking image in the mind of the reader. Wordsworth has been able to construct a vision in which the solitary traveler comes upon the solitary reaper with only her song to accompany her. In this image alone, Wordsworth has been able to capture the reader's imagination, expanding it by merely introducing the topic. Wordsworth understands the power of the image. In using it, he is able to facilitate the poem's premise of expanding moral and ethical imagination.
A second set of images is present when Wordsworth describes how the song sounds. Wordsworth understands that the poet has a challenge when forced to recreate a moment so that an outsider an fully grasp it. Essentially, he has stumbled upon an age old issue in writing: How can words be used to convey experience? Words are, by definition, a very limited means of expression. The web of language traps because what I perceive the words to mean might not capture the exact intent of the author. In order to avoid this, Wordsworth is able to use images to capture the sound of the woman's song:
No Nightingale did ever chaunt
More welcome notes to weary bands
Of travellers in some shady haunt,
Among Arabian sands:
Wordsworth continues this with including images of the Hebrides, "battles long ago," and "Some natural sorrow, loss, or pain,/
That has been, and may be again." In these images, Wordsworth pulls from human experience. We don't know exactly what the song is. Yet, from Wordsworth's use of images, we know what the song captures and what it represents. Like Wordsworth himself upon hearing it, our moral and ethical imaginations are expanded. We better understand the song through imagery. It is in this where one sees how Wordsworth has been able to use imagery to broaden individual experience, aligning ours to his, and making the subjective and personal notion a universal one.