Workhouse imagery
There is industrial imagery in the novel, depictions of old factories with terrible working conditions. There is dangerous machinery and a depiction of dirty, hard work in confined spaces. This shows the willingness of the mother to work to provide for her child, and it shows what single motherhood really feels like—constant responsibility with few resources and never a moment to lay down and rest.
Maternal imagery
There is mother imagery all over this novel. Women who take Esther in constitute her relationship to women as a girl, and her relationship to the child shows her as the mother, and in both the maternal cycle is shown. First a girl, then a mother. Then the mother dies and the girl becomes the mother.
Images of sloth and vice
The men in this story leave a lot of messes behind them. By indulging their desires, the men have become selfish and disreputable. In fact, the step-father steals the good life from his daughter, and her husband does the same thing twice, first taking her reputation, and then taking her inheritance away in a bad gamble. These are images of moral laziness, or sloth, and of vice.
Religious imagery
Religious imagery is spread through this entire novel. As especially religious people, it's not surprising that Esther's house has pictures of Jesus Christ. Then there are implied religious images, such as the Madonna and Child, the famous depiction of Mary holding Jesus, and there are interesting variations on these basic images as well, such as when Esther breast feeds the baby of the wealthy woman (potentially an allusion to Moses). Each scene is similar to a scene from the Bible.
Imagery of the run-down estate
The novel ends with the final stage of Esther's messianic journey. Now she must 'Go to her mother's house and prepare a place for her son,' which is loosely what Jesus says before his ascent into heaven in Christian scripture. This means that the imagery of the run-down estate represents redemption that only the sacred servant can provide. A final act of service from the suffering servant, to clean up the house she will dwell in.