Your answer may note some or all of these images:
The poet uses images of dimensions to express the pervasive nature of her love: “I love thee to the depth and breadth and height / My soul can reach, when feeling out of sight.”
Barrett Browning uses images that convey basic needs to impress that her love is like a necessity: “I love thee to the level of everyday's / Most quiet need, by sun and candlelight.”
Barrett Browning uses images of abstract feelings to convey the sincerity and purity of her love: “I love thee freely, as men strive for Right; / I love thee purely, as they turn from Praise.”
She uses images of implicit faith to convey the strength of her love: “I love thee with a love I seemed to lose / With my lost saints,--I love thee with the breath.”
She mentions old grief and childhood faith to imply the purity and intensity of sorrow and faith in childhood: “I love thee with the passion put to use / In my old griefs, and with my childhood's faith.”