How does Jonathan Swift use imagery in Gulliver's Travels?

Swift's use of insect imagery alludes to Europe’s morality as lackluster and hollow. Through the use of the Brobdingnagian King, Swift goes into the idea that the English were "the most pernicious race of odious little vermin that nature ever
suffered to crawl upon the surface of the earth." which was a famous view on the nature of humankind.