Marvell employs several images to express his love to his mistress and his overwhelming desire to consummate their love. His use of the pair of allusions - the "Indian Ganges", and the "Tide of Humber" - sets the tone. In reference to these images, Marvell asserts that not even the geographical distance that may come between them can dampen his love for his mistress. These images are appropriately followed by the metaphor of "my vegetable love" which "will grow vaster than empires". What Marvell suggests here is that his love, like a plant, has the faculty of growth that does not diminish.
Other images then follow involving hyperbolical references to the number of years it will take him to adore the various parts of his mistress's body.
But as the poem continues, Marvell abandons the earlier images and brings in the notion that his love for his mistress is bound by time. Thus we have images of the "winged chariots", "deserts of vast eternity" which suggest the ravages of time which both lovers cannot escape. Indeed, the image of "the grave's a fine and private place / But none I think do there embrace" heightens the catastrophe which awaits the lovers if they do not embrace.
As the poem ends, fresh images are introduced. These involve "fire", "predatory birds" and "rough strife", suggesting that there is no time but now to consummate their love and have control over their fate rather than succumb to it. This is perfectly captured in the image of the sun which the lovers "will make....run".