When you refer to the words or ideas of others in the body of your essay, you must make an in-text or parenthetical citation.
Keep these things in mind:
1. If it's on your "Works Cited" list, then you need to cite it in your essay.
2. When in doubt, cite it!
A few words about citing figures (images, charts, maps)...
You must refer to the figure in your text (see fig.1) and then place the figure near the text it relates to. Below the figure write Fig. 1 and provide a title or caption and source information. If you provide source information with your images, you do not need to provide this information on your Works Cited page. Source information can be provided in Note Form which is similar to MLA bibliographic entries but for a few differences. See the OWL link above more more information.
Fig. 1. Use of the terms vampires, werewolves, and zombies in published literature of the last 200 years. From Nathan Bransford; "Vampires (blue) vs. werewolves (red) vs. zombies (green);" Nathan Bransford, blog.nathanbransford.com/2010/12/fun-with-google-ngrams, 2010, Accessed 27 Sept. 2019.